Justin,
Not sure I can help with all the questions, but a couple of excellent sites to check out are:
http://www.kentuckylake.com
www.kentuckylake.org
www.explorekentuckylake.com
All three offer a lot of information, as well as lodging information and campgrounds.
As for camping, March can be cold. In March of '96 we had 36" of snow, but then I've seen February's where people are already mowing the lawns.
You can find a lot of pre-spawn large bass on Kentucky lake and Lake Barkley. These are two sister lakes connected by a canal. Kentucky lake extends down into TN, and is 120,000 plus acres, while Lake Barkley, which also extends into TN, is 65,000+ acres. KY Lake is generally clearer and has a better population of smallmouth than Barkley, and it is somewhat older and most fishing is done off shore.
These two lakes are flood control, but only drop 5 feet from summer to winter pool. They should both still be lower than summer pool in March, but you can easily find flooding situations that will have you fishing the flooded buckbrush and flooded grass. There is a Yellow Flower (Mustard plant I believe) pattern that is generally good in the spring. Fish the flooded yellow flower bushes for some very nice largemouths.
I'm not sure of any places that rent high performance bass boats, or tackle for that matter, but most of the marinas and the state lodges do rent aluminum boats with small motors.
I'm no help at all with the eastern KY lakes, like Cumberland and Dale Hollow. THese lakes are highland type resivoirs with deep clear water.
Good luck,
Danny