A rear-mount blade should be able to follow the terrain without digging in. If the blade is fixed it will dig in when you begin climbing a "hill" going backward. The blade should be angled to deflect snow to the side on longer runs. There could be a lot of side-stress on the hitch - make sure it's up to the task. Having the ability to raise and lower the blade is a huge asset.
If you plan to plow backwards-consider using some sort of backup camera. My neck is only good for 10-15 minutes - your results may vary.
If you get stuck pulling while hitched, backing up will probably be most difficult. Consider having a winch in your arsenal. A snowblower was previously mentioned-it would team up well with a winch in a difficult situation. A few shovels would also be helpful.
