Jrv, there are some "trail" issues that you need to elaborate on. How rough are the trails and are you planning to use a finish mower or a rotary (or flail) mower to mow them with?
Other thoughts...
For maximum maneuverability, you would want a mid-mount finish mower. If the finish mower would work on the trails, would you want a 60" (5ft) deck where two passes would get slightly less than 10 ft when overlap is considered, or would you want a 72" mower where a 10 ft wide path is pretty much guarenteed even after overlap is considered?
The B2910 (and I believe the B2410) can handle a 60" or 72" mid-mower. The BX choices are 54" and 60".
If you are going to use a rotary or flail mower for the trails, then you would almost have to go to the B2910 if you wanted to have a 60" mower. This would offer you the opportunity to have the mid-finish mower installed for one job and the rotary mower installed for the other (that combination would work for some and not for others).
As has been mentioned before, you can purchase an entire riding mower for less than a 3 pt finish mower. Mid-finish mowers are even more expensive.