Went through the same thought process as you for a pull behind mower for my property. I had 8 ft. wide ATV/UTV trails put in to make it accessible as the slope was just steep enough to make going sideways nearly impossible. Also plan on having a small chestnut orchard eventually with 40' spacing between rows.
Just happened to find a never used ProMow Gold pull behind 7 gang reel mower. Fairly expensive to buy new, but got a terrific price on it. Found it on Craigslist. Can configuire for whatever cutting width up to 11' 4" on the 7 gang or less by dropping off one or more of the individual mowers. I use 4 total on the ATV/UTV trails, which pretty well mows it all in one pass around.
No motor, gas, etc. to worry about and reel mowers cut grass the right way. The individual reels float to accomodate uneven terrain. Something to consider......check Craigslist, etc.
http://www.promow.com/products/gold_series_mower.htm
