my ..00001 cents worth. Having had the skidsteer at my place and the 45 hst, the skid steer had more lift and a bigger bucket, but my tractor was faster on the long hauls. I know this isn't your issue, as you have access to other equipment, but for me it was dissapointing that the tractor couldn't lift some things or move some things. The 55 handles larger attachments and has alot more lift capacity.
As far as road maintenance, I don't see any issues for a 45, just may take a little longer than the big equipment. I don't have a cab, and I really wish I did when the deep freeze was in my area. no fun clearing drifts in negative temperatures. All in all, I really do like the machine alot. It does amaze people from time to time what it can do.
Some of the other posters did point out an issue with the 45 if your going to use it around the house, it is quite heavy for it's size. With loaded rears, loader, and a 6' box blade, the thing comes in around high 6k-7k. something to chew on. Additionally, for your purposes, you may want to really consider the tires you choose. My industrials will leave ruts in the field if it is even remotely wet out in the spring and fall. Winter the ground is frozen, and summer it gets hard from the heat. Just something to consider.
Good luck with your pick.