Yeah, demoing is the best way to go if you're gonna be plonking down a good bit of money for a boat. Most shops (like us for example) will apply the cost of a demo as a discount to the price of a boat so you don't end up paying for the demo if you end up getting the boat. Some suggestions for your size:
Wavesport EZG 50-stable, forgiving river running player
Dagger RX 6.7 or 6.9-more playful, easy to roll river running player, take the smaller size if you want more play or the bigger if you want more stability, you'd probably fit well in both.
Dagger Mamba 8.0 or Wavesport Diesel 65-Both river runners with a bit of a planing hull and harder edges for surfing
Jackson Fun-Stable, river running player that has a good mix of stable and playful.
We've got everything but the Jackson boats around to try em' out, and we're having a sale on boats from now til' the 4th if you're looking to save some money.
2510 47th St #A1, Boulder