Congrats. I had longer track apex sleds. Xtx, Ltx. Loved my 12 apex xtx. Then got out of sledding for a couple years. Bought a 2010 apex and 2016 vector short tracks a couple years ago. Swore after that first season on 2010 apex my next new sled was going to be 137. I ride mostly on trail like you but I always felt when set up properly the mid length track sleds gave you the most options for the money. As a bigger guy. 260# I feel for me that 136,137” skid helps on the rough trails too. Like others have said in other threads on this subject, I’m sure you will be thrilled either way. I know my first 340 miles on my new ltx sidewinder have been pure enjoyment.