I own an integrally suppressed Ruger MkII. I would say that it is a fantastic gun if you don't intend to do a lot of shooting with it. As was mentioned, MINE cannot be disassembled for cleaning. I don't keep up anymore with what is out there in the suppressor world: I am sure people are now making integral .22 suppressors that can be taken apart.
Again, as was previously mentioned, .22 suppressors get VERY dirty. I am not a big gun cleaning guy. I mostly clean my guns when they show some obvious sign that they need cleaning (like malfunctions). However, suppressors for .22s won't tolerate that kind of treatment. The more you shoot one, the more stuff that builds up inside of it. It makes it very hard to get apart again, and it makes a huge mess when you finally get it apart. The last time I cleaned my TAC 65, it was like thick mud inside of it.
Which brings up another key piece of information: before you ever fire your first shot out of a .22 suppressor, take it apart and coat the threads with Never Seize. You will thank me later. One other tip: if you can't easily get the suppressor apart and before you do something drastic that might mar the external tube: use an impact wrench.
Another thing that may or may not mean anything to you. At one time I spent a lot of time reading the various on-line information about suppressors. They list all kinds of metered sound levels and all that. I spent the money to buy what was considered the state of the art suppressors that metered the quietest. Then I started shooting along side other suppressor owners. Many of the guys I was shooting with bought their suppressors more based on price than I did. In other words they weren't using these highly rated, much discussed cans. And much to my dismay, I couldn't tell the difference between my cans and their cans in actual shooing. Yeah, I believe that high tech electronics could tell the difference, but I couldn't. So, from a practical standpoint, I could have saved a lot of money by buying much cheaper suppressors (which again, sounded just as good as mine to my naked ears).
Based on this, I ended up buying two .22 muzzle cans from Tactical Innovations. The TAC 65 and the Quest. I am completely 100% satisfied with their performance. I shoot them all the time and have no complaints at all.
As far as threading the Ruger MKII, there are at least two ways to go about this (and I have done both). Obviously you have your barrel threaded by a gun smith. I had two of mine done and they turned out fantastic. Another option is to buy a new top end for the gun that is already threaded. I bought a Tactical Solutions Pac-Lite. Again, I have no complaints with it at all.
One last comment that may or may not apply to .22 suppressors. Don't buy anything rated for full-auto fire unless you are really going to use it on a full-auto gun. If you are anything like me, you read that it is rated for full auto fire and say to yourself: if this thing can take that kind of abuse, it should last forever with me using it, since I am not shooting full auto. However the suppressor will be needlessly heavy and bulky. I have made this mistake twice and now regret it.
One other point is that with a muzzle can, you can use the can on other guns. I am not talking about guns chambered for other cartridges, but other .22s. You can use them on that Ruger as well as any other .22s you had threaded. I love .22s and own a bunch of them. Rifles and pistols. And more than half of them are threaded.
You know the rest. In the books you have read
How the British Regulars fired and fled,
How the farmers gave them ball for ball,
From behind each fence and farmyard wall,
Chasing the redcoats down the lane,
Then crossing the fields to emerge again
Under the trees at the turn of the road,
And only pausing to fire and load.