I can't speak for the 60 series but on the 40 series the sub frame isn't hard to install or remove. I do it on the garage floor and use a floor jack. There's a way of using the tractor's hydraulics and the sub frame to do it. It takes me about 10 to 15 minutes. The blower is a little trickier to install. The expansion joint on the PTO shaft looks to be square but it isn't, it's actually 1"x 1 1/8" so if you are not careful you can try to slide it together wrong (think square peg into round hole). It does have a more standard connector on the end of the front most pto shaft but it's in an awkward spot making hard to pull the collar back to install/ release it. Other than that it's pretty easy too. Storage is an issue. The sub frame goes the full length of the tractor (it uses the rear draw bar to hold it in the rear).
What I tell everyone is if your driveway is straight then the standard rear blower is a good option. If you plan on doing sidewalks or if you have snow banks you'll be clearing then a rear drag (front facing) blower isn't going to work that well. If you have the money to buy a front blower then do it. Most likely any other option is going to be a compromise. But the OP said he wants to have a rear mounted sander so that pretty much means front mount driven from a center pto or swapping attachments in the winter.
I do have a Herd 3pt sander. My driveway is a little steep in spots and after a couple of years of back to back ice storms I found a good deal on a used one and rebuilt it so it's like brand new now. I didn't use it once last winter. The few times I had ice I used my grading scrapper's ripping teeth to break up the ice. It works pretty well as long as the temp doesn't plunge to below zero before I can get to breaking it up.
The biggest problem with the spreader is the amount of gravel I go through. With a 3/4 mile long drive in the hills of Vermont it can take quite a bit of sand. The hopper is at least 3' high and takes about twenty 5 gallon sheet rock buckets to fill it. I usually have to fill it twice. That's a lot of gravel to move. The other issue is sand will freeze to the inside walls of the hopper if it's really cold out. The Herd spreaders have an agitator that bangs the sides of the hopper but it's not perfect. I could mix salt in to keep it from freezing but that's just more work. Every other year I just get a dumptruck load of sand delivered, maybe 15 yards. By mid January it has a thick layer of frozen sand that you have to bust through to get the unfrozen sand. I use my backhoe. If you had to do it with a pick axe or something it would be a job. I've always wanted to get a shed to put the sand in and get a small conveyor belt to load it but haven't yet.
