Worth of my truck?

As much as I hate to say it, I'm thinking about selling my truck, It's a 1959 B120 4x4 flatbed truck. the PO did all the bodywork, and there is absolutely no rust anywhere on it. The paint job is pretty good, but could use a wash and wax. I use this as a truck, not a show piece.
The tires are in great shape with plenty of tread, (Bias ply street tires) and it has the big six split rim wheels. I basically rebuilt the front axle, with new trunnion bearings/kingpins and new spring bushings. New brakes all around. The interior is nice also, the original gauges don't work, so I installed some aftermarket gas/oil/temp gauges. the speedometer works but is way off.
The engine is a 304 that the PO had transplanted in, it was previously rebuilt, runs perfect, no smoke, no knocks, the clutch is great, the 4 speed tranny shifts great, 4x4 works great. it has the HD dana 44 front closed knuckle axle and the rear International corporate RA10 axle. I replaced all fluids, greased everything, everything works as it should. (except for the horn). I installed the flatbed and the receiver hitch, it has wiring for a trailer, but no trailer brakes, and no 5th wheel/ gooseneck hitch.
what's a good price for it? I'm thinking $4500 - $5000.

I think you may have trouble getting that much. The problem is it is an older truck, and for that money someone can get a newer truck with the advantages that brings, So that limits you to someone looking for a semi-restored older truck which narrows the pool a whole lot. You might find someone, but it will take a long time.
Another way to look at it is to look at vehicles that have that asking price, and see what they offer compared to yours. Fuel milage, parts avaiablity and such. Then ask yourself what does my vehicle offer that these others don't? Emphisze that in your ad. Restored vehicles are a hard sell because, what makes them have value is the condition, which will be spoiled if used as a daily driver, so you need someone willing to spend that kind of money for a toy that will not be driven. For a daily driver, a 50's vintage truck has a lot of drawbacks, (again, mileage, parts etc) when compared to a modern beater
It is easy to sink a ton of money into a restore, and little if any will be re-coup'd if sold. Execpt for a very few exceptions (Think Berret-Jackson autions) this is true.

CB is right, as much money as I'm putting into my vehicles, I don't really expect as much back, same reasons. try looking on ebay or craigslist for an idea. Then express how yours is better than... I'm glad that it has 4 wheel drive, that should help. SuperScoutSpecialists.com has a vehicle value guide, but it won't reflect prices any where in the country.
Wish you luck with it. Bill

you might also try NADA http://www.nadaguides.com/