its best to run it on the trailer without the driveline hooked up.  get timing set, carb close to dialed in.  just realize that theres no load on it like there would be in the water.  so idle, etc can be off by a little once you get it wet.  bring some tools with ya on your first trip out.

Imo hook up a water hose to the motor I front of your house. Get her idling at the right rpm for about 30 seconds and slap the throttle a couple of times make sure she doesn't die out or start acting/idling weird. Pack a tool bag, couple of wrenches, timing light, vacuum gauge, carb tuning kit and most importantly an ice chest full of beer...The last one always worked for me...hit the closest lake with a buddy. Don't take a whimp, someone that can hold on to the boat and kick hard with his legs (just in case). Trial and error speaking here...have had boats running perfect for 5 min om the trailer with pump connected and disconnected then you launch them and they are garbage...had boats that just fire up in front of the house, barely idle right on the trailer and are monsters in the water...depends on motor pump engine etc. Pack your tools, strong buddy to help ya, launch and tune. Plan to be there the whole day.

Ps: Bring a pen and paper so you can record rpm, throttle and all the weird stuff the float is doing.