If I purchase the ACA maps, is a gps necessary? If so, would you recommend one?I opted to not use the GPS when we did the TA in 2007 and on more recent tours only used my phone gps to find specific services. The AC maps are easy enough to follow without using the gps and it is nice to not be too battery dependent. I leave my phone turned off all day and only turn it on when using it to conserve battery, but it can be fired up as a reality check on location. On the TA I pretty much never found that necessary.
Some folks do prefer to go turn by turn on the gps though.
Also, any thoughts on camping? I was planning to camp my way across, though I was going to look into the warmshowers option as well.In the whole middle of the country there are usually free places to camp most nights. That is a little less true near the coasts. Free and cheap sites are typically listed on the ACA maps and after using them a while you get to know what will work and what won't even without the maps. I did not find warmshowers.org all that useful on my tours and only rarely stayed with WS hosts. I prefer to decide where to stay at the very last minute and most WS hosts prefer a little notice.
I did get invites to stay with folks here and there. Between that and staying in town park picnic areas, church yards, and so on we averaged under $5 a night on the TA for camping/lodging.