Josh- The Johnson's are undoubtably 2-strokes. The Nancy H is right on about the rub rail. Mine pops out similarly whenever I "Kiss" the dock a little to emphatically! Have considered seating it more permanently with some removable compound, like silicone rubber, but have never done so. Not really a problem.
This boat will be a considerable project, just to do the cosmetic stuff, but that's only a labor of love! That's the easy part. Since I have a similar model, I can advise you on some of the things I did in order to restore mine to first class condition. These need to be considered from a time, labor, and cost standpoint. Here goes:
The engines probably need a complete tune up. This would include replacing lower end gear lube, new water pump, plugs, through cleaning of the fuel system and replacement of filters, compression testing, carb synchronization (if necessary), ignition timing, idle adjustment, dyno testing, and a complete over all inspection. In addition, my service department recommended I replace all the fuel lines and purge the tanks of crud that accumulates over the years. Did all of it on my Evinrude 90 and Johnson 15 motors at a cost of about $500 four years ago. (Bay Area price, don't know if the labor is cheaper up there.)
There will be other costs. I needed a cracked window replaced ($45 for the glass -I did the installation), 2 new batteries (say, $6o or more each), a broken VHF antenna replaced (about $100 for a good one), new lines, lots of small miscellaneous electrical parts (fuses, bulbs, wiring, solderless connectors, etc.), clear urethane finish and sandpaper to refinish the handrails and renew the glaze on the Decaguard interior, loads of cleaning and polishing agents, spare tire and mount, and eventually a few larger projects that can be done much later, like a windlass and cabin heater, etc.
Check out all the electronics to see if you have any dead warriors.
The trailer is another issue. A new one will cost something in the neighborhood of $3000 or more. Finding a good used one would be a less expensive way to go, but they're usually not easy to come by, especially one that fits the specific boat. Usually one winds up buying a used trailer that will work with some modifications/adjustments to the bunks/rollers, balance point, bow post/guide, side guide-ons, etc.
Then the trailer has to be serviced. Wheel bearings need to be repacked, seals replaced. The surge brakes will need inspecting and adjustment. I had to replace the front unit which incorporates the coupling hitch and hydraulic actuator (master cylinder), and replace the brake linings. This ran about $350 at a trailer shop. The lights had to be trouble shot and made functional- Did this myself, $5-10.
After about three or four months of use and a blow out, I decided to replace all four tires and wheels, keeping the best one of the original four for a spare: $400 from Cabela's. Spare tire mount $35+ $5 shipping.
You can probably find a used trailer of sorts for anywhere from $800-$1500 or more, depending on type and condition. By the time you get it up to decent road standards (if you plan to trail much), you'll probably have $1400-$2000 in it. The hard part is finding a suitable patient to undergo the surgery!
Don't forget sales taxes, licences and registration fees. Here in Arnold's California, this can cost almost $200 on a $20,000 boat (!!!), which is why most people get a second Bill of Sale indicating a lower sales price from the seller to reduce the tax bite.
What I'd do if I were you would be to look up all the archived want ads on this and the C-Dog site to see what the average asking price has been for a similarly aged and equipped boat. Then deduct all the anticipated costs from that, and figure the absoloute max you would be willing to pay for the boat, then go and try to get it for as little as possible. At least you'll know your own bottom line and what you'e getting into!
This is not meant to be discouraging, but if you've never been down the Great Yellow Brick Road to Boat Owner's Poverty, you just might want to get some insight into why boats are sometimes refered to as a "holes in the water into which you throw money". "Irregardles", boat ownership is immensely FUN, treading water on top the Deep Blue Sea with the Devil draining you pockets from below. Welcome to the club!
Hope this helps and isn't discouraging. I also wrote it in such a way that other persons in the same situation later can use it as a reference, knowing that you already understand some or much of it. Joe.