Well I live on the Yellowstone up from billings about a 4 day paddle....
the Yellowstone is a series of drop-pools and rated Class 1-2 however we hare still getting pounded with snow and anywhere from 4-11 feet of snow above my house in the mtns....so we are going to have a huge runoff....most likely highwater will be dangerous from Mid may to first week in July!!!!
With your lack of experience I would put on near Three Forks on the Missouri....from there you could have a 2-6 days trip anywhere. Contact me so I dont type a bunch of worthless info for you when i would like to know the specifics and your seriousness etc. Great paddling out here.
1 Canoe/Kayak Trailer
EZ-Dock modular docks
Kindle / iPad Cases