I don't think you have to "warn" other parents about your home. Warn them about what? That you have certain kinds of toys? If it comes up you can simply say "we don't watch television" or whatever if they are suggesting that.
I also have an active kid, and he definitely learns by trying everything (or, trying to break everything??). One friend's mom said to me that the toy companies should hire my son to test their toys for safety and durability. Your calm, careful daughter probably is like that from a combination of basic temperment, age/development, and her environment. Also, remember that for the guest child, no matter what their own home is like, visiting a new place is very stimulating and it may take several visits before the guest child is comfortable and acting like him/herself (whatever that is, because they are changing so fast right now too).
We did lots of "playdates" (often very casual, make loose dates to meet in the afternoons, etc) starting before age 1 at the playground, then we started with certain friends at eachothers houses-- and started dropping off the kids to get a dinner out, to work for a few hours, etc. I am a student mama and live in a community with many others, so it was wonderful. I learned a lot about my son and his friends watching them, and really I do think the kids learn a lot from eachother, they gain social knowledge, they learn to play in totally different ways, their language skills make huge gains having to communicate with other people, they learn empathy (slowly!), they do become very attached to certain friends.
We also "prepared" the house for playdates by removing things of which there is only one (recognizing that sharing just wan't going to happen), things which are fragile or hard, or to which our children were particularly attached. Also just slimming down what is out, so that the inevitable mess isn't too huge. I found that wooden trains, for example, could be played with almost indefinitely with minimal fighting. I also broke up a 1-3-hour playdate with different activities-- play inside, snack, play outside, come in and sing or read a book, play some more, etc. Sort of like preschool. Not until they were about 3 did having a friend over get EASIER for me than just having one (and only certain friends lol!) I would consciously try to involve them in something, and then step back if possible, but with some kids, and with the synergy between some kids, that isn't always possible at this age. Mostly parallel play at this age. But you know, I think that they do enjoy the company of friends, even though they can't play "together" yet.
"Sharing" is extremely hard at this age. You can try to have multiples of everything (which sort of helps) and with a lot of adult support *some* kids can learn about turn-taking and simple cooperation (for example, pulling a wagon together, filling and dumping water containers) (I would ask myself: how can they "share" an item that only one person can use anyway? I found it helpful to imagine if I was constantly being asked to "share" my computer, car, etc...). Even when it does happen with 1-2 year-olds, joint activity/sharing requires adult modeling and monitoring of turn-taking, compromise, etc. I am not sure they can "work it out" on their own-- with my son he usually ended up clobbering the other kids to get his way-- or even just to see what would happen-- (he was and is strong-willed, quick-tempered, very verbal, and very strong and coordinated physically), so at age 1 I kept a close eye on what was going on, and I often felt I had to intervene to help him keep within the bounds of acceptable behavior. Now that he is 3 this is much less of a problem!
My belief is that playdates aren't "easy" but that social interaction with peers is very important, especially for only children (like mine) who wouldn't get it otherwise. I can tell when we get together with kids who haven't had a lot of exposure to peers... they orient all their interactions towards the adults, and they lack a lot of coping skills for the unpredictability of kids! I guess while playdates aren't necessary, its been worth it for us. I love the mom friends I've developed, and I love to see how my son really does care about his friends (who also range from 2 years older and younger than him). Its also such a relief to have back-up childcare when we need it, since I have no family close to me.
dissertating mom to three