I wouldn't go with nothing less then one of these http://www.buddyramp.com/default2.htm

When I bought my Toro 36 gear, I had these metal ramps that are about 5ft long, one for each wheel. I use them for snow blowers and 21" mowers, lawn vacs etc but when we tried loading the 36 it took 3 guys. When I took it off myself, it was so dangerous that I went out and bought a trailer.

 

walk behinds arent the easiest pieces of machines to get up any kind of ramp and when you have to go that high i would def look at that link the second poster sent you.

that looks like a great choice but be safe, they dont like going up ramps

 

I use 12 inch wide planks with ramp ends (available at any hardware store for around $30) and they are about 4 feet long. They work just fine. No issues at all. I have a Better Quickie 32 but I wouldnt think a 36 would be that much different. You dont always have to spend a fortune for function...

 

Uncurved, straight plank ramp kits recommend a 15 degree incline. To get the 15 degrees, a straight ramp should be 3.86 times the height of the bed. If bed is 20 inches high, the ramp should be 77 and 1/4 inches long minimum:

20 x 3.86 = 77.2 inches

The height of the bed is what determines the length.

3.8637 is the inverse sine of 15 degrees.

 

Occasionally put mine in an average 4wd Chevy with 2x8s with ramp ends. 8' long. It's a little too steep. Going up is ok. Coming down is sometimes scary. Deck catches both ways. Also, dropped it a couple times on wet boards or had 'em slide out. Wouldn't want to do it every day.

 

I really really really reccomend a trailer. It's not so much getting the wb into the truck as getting it out safely. You'll wind up wearing that thing if you do it very often.