Inspecting a used boat

I am a fisherman with a limited budget, but I'm looking for my first bass boat I have run across alot of late 80's & early 90's bass boats for rather cheap price if you can get to them in time seems they sell fast even though what I find cheap is usually about book value most I find are way over book value with no shame.

When looking at a boat is it safe to climb in the boat on the trailer & see if the floors are solid ? I am about 270#'s and don't want to snap the hull in front of the owner lol.
Also when checking the transom I know to look for rust or coloration run off from the bolt holes, but how rough do you get with the outboard to determine transom stability?
Most water test are not an option for me because most boats I can afford need some kind of work or another, just don't want a boat with a rotted core or one with low compression or bad transom most other issues I think are manageable to me.

So any tips you can pass on would be great

Absolutely you should climb through the boat. Run all the accessories, test the pumps (at least listen for them to run), run the motor on muffs, check for soft spots, look inside compartments, open all the access hatches and check the bilge. Look for wiring corrosion on the battery and any visible terminals.

If your serious and still like it ask them to drop it in. Then inspect the trailer. Check for rust, brakes, does the actuator slam?, bunks are fully carpeted, loose fenders, loose bunks, etc.

Follow to the ramp and check for lights and see how the boat tracks behind the tow vehicle.

Take it for a spin. Watch how the owner is handling the boat. It will tell you alot about how the boat was taken care of. Are they familiar and comfortable and smooth dropping in? Ackward? Slam the dock or forget the plug?

How hard was the cold start? Did he warm it up prior to you arriving?

If everything goes well and it's the boat you want, ask for an opportunity to have a boat (hull and motor) survey completed.

It sucks to drop a few hundred dollars on a survey but it could save you thousands.

You can agree on a price contingent on the survey.
Negotiate final price after survey.

You should be able to get pretty rough with the outboard to check the transom. I know it sounds weird but smell the compartments, if it smells musty it's probably a pretty good indicator that there's water sitting somewhere. STEP ON EVERY SQUARE INCH OF THE DECK/FLOORING. And there's no better time for the hull to snap off than in front of the owner. If it's that weak you want to know before you fork over cash.