Prepare for a major hemorrage of cash to do the paint and bodywok on your truck. trucks are alot of work to get right, the bed alone is a ton of labor, I have done sveral of these trucks and currently own a 67 Suburban. The thing is if you are handy you can do alot of the grunt work to save money, I would try to find someone who has done a truck or two so they can honestly let you know what it will take to get it done. As far as time goes that all depends on the condition of your exsisting truck and what you want to see in the end. 5,000 for a low end driver to 25000 for a show quality trailer queen.
Dont get all your nice mechanicals in place and take it to a paint shop though, you will have overspray on everything and they will have to dissassemble alot of your work. Restoration/car building has a sequence, think it through to save yourself frustration, money and time.
Find out where all the local old car shops and builders are and spend some time there to get a feel for what goes into a paint job, most guys are proud to show you what they can do or have done.