Double duty on your home place and the 120 acre place and with your Dad and brother's 600 acres? Or is that triple duty??
IIRC - you posted that the dealer is offering ~19,000 for your 3520 and he wants ~27,000 difference -- close enough for my "rounded" head?
I just bought a 5075M for $61K - shipped to Alaska. Quite a few options; including a $3K HD rear blade.
Just for discussion's sake... drop the $3k shipping, the $3k blade, drop the optional cab/air seat $900, 563SL loader with 3rd SCV and mid SCV ~$2.5k, rear wiper, rear work lights $500, rear weights $700, front wheel spacers $500, rear fender EH control $400....
See where this goes -- the M series is only a few $K more than the E. And it's alot beefier where it counts! The rear transaxle and the EH 3pt. The added hydraulic capacity.
If your Dad and brother are gonna be working the tractor on the 600 acre place (or you're gonna lend a hand with your new tractor) spend some time looking at the machines; shoulder to shoulder.
You might just find that the longer term "value" is the better investment.
Good luck.
AKfish