My Wife and I did a one week tour of Big Island in February 2008. I think I would want a little bit more time on your tour then we used. We flew our touring bikes with very small granny gears with us on this trip. NEEDED THE GRANNY GEARS. The grades are not steep yet the winds on top of the grades make them feel much steeper at times.
A brief outline of our trip.
Arrived in Kona later Sunday evening and stayed at the KONA SEA SIDE HOTEL. A nice modestly priced hotel (BIG PLUS the staff looked after out bike boxes for the week until we returned from our riding).
Monday an easy day about 23 miles uphill in hot to warm weather, we are on the dry side of the Island. To Hookena Beach campground. Watch the half ton trucks, very rude drivers that dislike cyclist. Very scarey to be helled at well slowly climbing hills in traffic on a narrow paved shoulder. (This was the ONLY day we had trouble with traffic and is a short section of the Island to deal with the problem) Be prepaired for the halh ton drivers and do not let these very few drivers on Big Island get you down). Best problem Male driver of the day ...he was just letting us have it with both barrels of his limited vocabulary as he passed, we were approaching a stop light.... At the light we pulled behind him and his wife in the passenger seat was letting him know in very clear language what she though of his treatment of cyclist. We laughed for the next few miles over this. Should carry some evening food and breakfast starting food as there are no stores around most of the camp sites on the Island.
Tuesday we are now relaxed and into the ride, yesterday's short ride was planed as an easy ride due to our jet lag . Ride to Punalu County beach about 48 miles. A very lovely day with little traffic and wider paved shoulders. When you pass stores stop at them as they are far apart, and pick up the supplies you need for the days ride and evening meal/breakfast. As you approach the crest of the headlands around Ocean View the winds will get strong they only last for a short number of miles before you are on the down grade. ( Remember to get coffee in Ocean view cafe/ there is a large store to stock up at here as well). The ride down to Punalu beach is down hill mostly from here and an enjoyable and wonderful afternoon of views.
Wednesday Up hill for 40 miles to Volcano, on wide paved shoulders. This all up hill at a shallow grade for 40 miles, but it is a continuous grade for the day there are no breaks. There is a town called Pahala that has most of the basics and great coffee, stop here as the next services are at the end of the day in Volcano. As you climb you pass elevations every 500 ft. The grade is constant, so you can judge your distances by using the elevation signs. The final 6 miles the winds will pick up as you crest the volcano. The grade gets easier just at the perfect place...the wind and heat will have taken a light toll for dodays ride and you are glad that it is easier for the final miles. The Food at Restaurants was the best that I can remember on many bike tours. We stayed in a lovely cabin in Volcanoe, ( Volcano Inn) there is a campground, but it rains a lot in Volcanoe and I knew we would need extra rest after this days ride.
Thursday Road to Lauphoe Point Campground about 50 miles, But first half is all down hill. We were expecting rain alll day. Yet just as we started our days ride the sun came out and we followed a break in the clouds for most of the day. A fantastic days ride good shoulders. Along the Windward side of Big Island we left the belt road and took a few of the scenic side roads, these are well signed and only add a couple of extra miles to the ride, yet take you through rain forests and past tall waterfalls that you will remember for years. Again there are few services so stock up on your food when you see a store. We stayed at Lauphoe point campground and it lightly rained through the night.
Friday road to Spencer Beach campground 42 miles. Breakfast coffe along the road talked to truckers, they have ben passing the work along the belt road that there are two bikes going around the island. The trucks have been great of this trip and it is/was a reflection of a population that was enjoying life and enjoys watch others enjoy their lives. Had lunch in Honokaa and took the "Old Mamalahoa HWY" up the mountain. This is the old road it is steeper, yet views are better and there was no Traffic. Mid afternoon break in Waimea then down to Spenser Beach.
Again there are no services at the campground so remember stock up at Waimea or ride back up hill 15 miles and a vertical gain of 3000 feet. For Balance of the trip stay on the asphalt with your bike! We are new to this environment at learned about deserts thorns after a 200 footbike push through the sands.. Four flat tires and a dozen thorns in each tire, we spent a lot of time cleaning these tires are patching. Carry spare tubes we did and we needed them. Also SPENCER BEACH gets booked out so if you do not have a reservation you are out of luck and will be told to move on regardless of the daylight conditions. I would book a night plus and minus each side of a stay at spencer park if there is any question on your dates. ( it costs a very few extra dolloars, yet your options at night time are few!)
Saturday ride back to Kona 34.1 miles Mainly flat , but the winds!!!!! We had so very strong side winds first thing in the morning about 30 miles per hour. My wife is able to ride up hill in a granny gear all day with never a complaint, yet the side winds here were driving her off the road even as she walked the bike. The only way we could get through this section was to transfer all her panniers to my bike. This allowed the wind to blow throw her front wheel and allowed the trip to continue. My bike was double loaded, yet we were on the flats+/-. I tacked as in a sailboat on the 12 ft wide paved shoulder for the next few miles until the wind became a tail wind. Once the wind was behind us the extra panniers transformed my bike into a clipper ship and I did not turn the cranks for about 30 miles, as my wife happily lead the way along at 30 miles per hour pace.
Sunday was a relaxing tourist day in Kona and a mid night flight back to winter.
Be prepared for the rain, it rains hard on the windward side of Big Island, it is a Desert on the lea side carry lost of water. Reservations are a must! Carry spare tubes and have good gearing on your bike we have 20 inch gears for the tough sections...they are short but gearing is important. Watch your Air line fares in relation to bike costs..it cost almost as much to fly the bike with some airlines as yourself. Check the carriage rates before selecting the flight. Your panniers acn be waterproofed by inserting glad garbage bags before you pack them. TRAVEL LIGHT.
We are in reasonable shape, yet we are not racers, you should have a reasonable baseline of riding miles before you start your trip and plan a short first day. It is a lovely ride enjoy it, ride in the direction we did as the paved shoulders are ocean side and the paved shoulders are only on Ocean side across many of the bridges.