I just got back from a version of this route 10 days ago. I had a fantastic experience on this ride and you are in for a treat.
I left from San Francisco and took the Western Express to Pueblo then (apostate alert!) drove across Kansas and Missouri and picked up the TransAm route in Illinois and rode that through Va. for 2700 mile in 31 riding days. I was "credit card" touring so every night was a hotel and most meals were in a diner or restaurant. I will keep my comments here to what you directly asked but I will include my email for anything else I can help you with.
Just for some background, I'm 54, started riding at 14, raced for 15 years and have been a recreational "roadie" since. I ride between 3500 to 5500 miles a year depending on work, weather etc. This was the first time I ever had panniers or even a rack on one of my bikes.
- I used a road bike with a compact crank (34/50) and the cassette was 12-28. That gearing was fine for all the hills I ran into (btw: the steepest stuff is in the east), but I was travelling very light.
- Traffic was generally very good as were the roads. There were individual spots that is was unpleasant. For me the worst place was Rt 50 east of Monarch Pass as it runs along the Arkansas River in Colorado. Maybe it was because it was a Saturday but there was a lot of RV traffic and they seemed totally unconcerned if they tagged me or not. This was very much the exception.
- I used clipless pedals with carbon soled road shoes and had a pair of very light weight sneakers bungied to my rack where they were immediately available. I would do the same again.
- I didn't do any camping but it seemed like I passed a fair amount of campsites or places you could wing it.
- Tires were the only real mistake I made. I was riding sew-ups (you may have to look that up) and while they were heavy sew-ups and relatively wide (24mm) they were no match for a thorn that grows out west that I was not familiar with. Five flats in the first 1200 miles, then I didn't have another for the rest of the trip. If I was to do it again I would switch to clinchers and go with a 28mm tire. There are some torn up shoulders you will sometimes be forced to ride and you'll be glad to have the wider tire. My guess is 4 tubes and two tires until you get to Pueblo should be fine and there are bike shops along the way to re-stock. Once you get out west bike shops become MUCH FURTHER APART. You will want to load up in Pueblo.
- I brought 2 pairs riding shorts, 2 summer jerseys, 1 winter jersey,2 pair socks, 1 rain shell, 1 pr tights, 1 pir very light weight street pants, 1 shirt, and 1 pair swim suit. Add your medical stuff, toiletries, and tools....my panniers weighed 15 lbs with everything except extra water which I always had to carry out west. But I had no camping stuff.
- as far as food...you eat and you eat, and then you eat some more, and then you have 2 desserts. On the bike I ate a lot of Nutter Butters and Fig Newtons and I always had Peanut Butter, dried apricots, and a bag of tortillas for lunch if there was no place to stop. I didn't lose a pound on the trip.
- My trip cost $6000 and most of it was hotels and restaurants. I think it can be done for less than a third of that easily.
My final thoughts : Get yourself in really good shape before you leave. The hills is far western Va and eastern Kentucky are steep and they keep coming and when you get out to Nevada (& some places in Utah) there will be days where it is 80 miles + between anything, not even a house or a ranch, and it will be hot, and there will be 2 or 3 mountain passes. You will need lots of carrying capacity for water. I bought 2 pvc 2 litre bags for water that roll up when not in use and weigh almost nothing. Make sure you get these. Link is below.http://cascadedesigns.com/platypus/water-bottles/platy-bottle/product
If you want, you can email me directly @ email@example.com