Set up a seperate gmail google email account to protect your main email account. You can also set up a google phone number (for free!) which will give you a new phone number that you can then forward to your main number. This way you can post both an email and phone number on Craigslist and then discontinue them after the sale. Otherwise, scammers will harvest your contact info and will badger you with spam afterwards. Keep in mind that if you reply to a text with your phone they will have your phone number. Stick to email with your temp email account until you are convinced the buyer is legit. Then call him, and block your caller ID.
I second the comments about taking off your high $$$ accessories. You can either sell them on ebay or offer them to the buyer AFTER you fix on a price. Trolling motor, fish finder, troll plate, downriggers, extra battery, props, bimini, whatever.
Or... set a price for your boat stripped, and one with accessories. I will negotiate on my items to a certain price, then tell the buyer that getting below this price results in things start coming off. Avoid the hassle by selling your boat bare-bones.
Same with the test ride stuff. Settle on a price first given a checkout ride. Take a deposit, even a small one, and that is non-refundable but applicable towards the purchase price.
If a buyer wants to have the boat checked out, they have to pay the shop in advance. You will haul it there and back, and the shop has to prove to you that they have received a pre-purchase inspection payment before you leave your driveway with your boat.
Make sure that the registration for your boat and trailer are current. It sucks to get a buyer on the hook only to get kicked off the ramp because your registration is expired.
Clean the heck out of your boat before taking pictures for craigslist. I am amazed at all the for sale boat pictures I see with the boat full of leaves, beer cans etc. If the seller could not be bothered to clean out the boat for pictures, you know they probably didn't maintain it.
Describe the boat well with text. Craigslist adds with lots of pictures and good descriptive text get more responses than "boat for sale" and nothing else.
In terms of detailing, clean the engine too. For trolling motors and dark plastic trim and things, I recommend using "Back to Black". It really does a good job in restoring dark color.
Empty out old fuel and slowly add it to your car. Make sure you have fresh fuel in the boat tank prior to a test ride. I went to test a boat I was going to buy, and I drove 3 hours to a lake. The seller drove 2 hours to the same lake, and the boat would not start. I was pissed, and he was disappointed.
I also second being very up front with whatever is wrong with the boat. Be honest, and be fair. What comes around goes around. Also be reasonable on your price. Depreciation happens. That is the price of owning our boats.
Good luck!