Re: Moving on up! LOL!
If you do stick with gas a 2hp motor should be more than enough. Keeping it small will prevent it from changing the boat's balance too much.
A paddle is the cheap and reliable solution.
Half of the fun of sailing a motorless dinghy is short tacking in narrow channels.
boats that I sail on regularly: Pearson 28-2, Rondar 505, Yankee 30, Blanchard Junior