If you have the entire bed assembled, grab 3 buddies, some cold ones, and lift it on. Its not too bad. I've removed beds this way.

I have also installed a one ton bed without the bed wood in with some pals. Getting the bolts in weren't too bad under the truck either.

1970 Chevrolet C10
Grandpa's -- My first truck -- In progress to shiny
Follow the build in the Project Journal
1950 Chevrolet 1-Ton Dually
"Ole Red Girl"
In the Stovebolt Gallery
More pictures here
1951 GMC 9430 1 ton dually--Shiny! | 1972 Chevrolet C20- Rusty- the puzzle box lid for the C10 | 1962 AMC Rambler American- my wife's
Parts trucks-
1951 GMC 9300 | 1951-GMC 9430 | 1951- Chevrolet 1300