most of the answers to your questions will be found on the "gator" web site. they even have a builders forum where you can learn about building the gator designed boats and ask questions about building them.
http://www.gatorboats.com/
the designs look well suited for first time builders, and i suggest that you consider a two man (or larger design. as far as moving the boat with out a trailer, that's not a problem. you can buy or build a wheeled dolly or cart to move the boat around. to move our 14' wooden skiff, we use a dolly that clamps on the transom. here are examples of some.
http://www.garelick.com/product.php?pnumber=71050
http://www.discount-trailers.com/boat-dolly.htm
home made boat dolly
http://www.youtube.com/watch?v=D0xsXvenB4k
as far as carrying the boat on a short bed pickup, my suggestion is to put a single roof rack on the top of the cab and use a trailer hitch boat mount on the hitch.
http://www.backcountryracks.com/thule-goal-post-hitch-boat-rack-997.html
here is info on building your boat from the web site
"How do I finish it?
We recommend an epoxy finish, just because it will double the life of the boat and make maintenance much easier. The interior can just be painted with a couple of coats. On the exterior, it's a good idea to use a 6 oz. 3-6" fiberglass cloth tape reinforcement on the seams, and a 4-6oz. cloth on the exterior bottom if you think you'll benefit from extra abrasion resistance. Epoxy always goes directly on bare wood as the first coat, it must saturate the wood to provide it's benefit. It will not only prevent any water from entering the wood, it will also sink into the fibers, bonding them together and making the wood into a single solid mass. A wooden boat properly finished with epoxy will have the same lifespan as a solid fiberglass model.
When you're ready to paint you must wash the cured epoxy to remove the waxy "blush", sand it with a 220 grit until there are no shiny areas then paint. The best finish is a polyurethane marine paint, it's a bit more expensive than standard exterior oil, but it's really worth it, it has more solids and will resist abrasion and hold it's shine longer. A standard exterior oil deck enamel has been a favorite for decades and is still a good lower priced option. Unlike latex paints, oils are usually priced by their % of solids, so when you buy a cheap oil paint, you're getting more solvents and less solids, so part with the greenbacks on this option and you'll have to do less refinishing and the boat will last longer.
If you don't use epoxy, be sure to thin down the first coat of oil paint to ensure a good saturation into the wood, then apply 2-3 more topcoats".
as far as cost, suggest that you add an extra $200 to their estimate. so if they estimate $100 for materials, then the real cost will be more like $300 to $350. depending on what wood you use and where you purchase your epoxy and fiberglass. if you take the time to seal all wood surfaces with epoxy, finish the boat with marine paint and keep it protected from the elements then your boat can last many years. we have a small plywood skiff that we built in 1994 that still looks great.
suggest that you take a look at clear penetrating epoxy sealer to seal all surfaces and edges of the wood that you use in you boat, then you can use laminating epoxy for the next coat and with the fiberglass cloth tape filler. here is more info on the cpes
http://www.rotdoctor.com/products/cpes.html
more info
http://www.rotdoctor.com/products/product.html
hope this helps