This was us two years ago. At the time, I had a newborn, a 4YO and a 5.5YO. We were doing Kindergarten at home and going to church and occasionally showing up at the local homeschoolers' group (75 families or something...surely we could have met SOMEONE?!). Nope. We were pretty lonely.
However, that year was the year I really developed a path for directing our homeschooling. I'd thought we'd unschool, but it didn't feel right. I'd always been interested in Waldorf and we dug deeper into that. Once I had that piece set in my mind, I was on the lookout for other families who used the same philosophy. And I met two other families (one of them here on MDC)! They were an hour away but we met a few times and then another Mom who had been trying to get a group started introduced us to a few more families. We started meeting once a week. About six months later we hired a teacher to do a handwork class, and then...somehow...it all took off! I still am not sure why, but now we have a group of 47 families within about a 90-minute radius. We have smaller groups that meet regularly (like a playgroup in one area, a co-op in another area and a teacher-led co-op in yet another area). Once a month the whole group gets together for a day. It's loosely structured...we meet outside, bring lunches, have a bonfire, build forts, organize some games to play. Sometimes there is a craft or a song to learn or the Mamas need to discuss a group business item. The kids mostly run around and we Mamas chat and make connections. It really helps that we all have some basic values in common....I know my kids aren't going to feel 'wierd' that they don't watch TV or wear logos on their clothes or eat doritos or whatever. (Of course, as homeschoolers, we all have our own ways of interpreting Steiner's ideas and our own levels of immersion into a Waldorf lifestyle...but the point is that we do share a common thread) Now, two years on, we have a really great circle of friends. Each of us (me, DH, kids) have made some really wonderful connections and now we have plenty of playdates. We have one this afternoon!
Here's the thing. I think it's really important to figure out what you are looking for. I mean, you don't want to just force two like-aged kids together just because both are available, right? Looking back, I think we probably KNEW plenty of families who could have fit the bill, but nothing came of it and we felt lonely. I now think that this was because a lot of the families we were trying to connect with just didn't share enough of our values and it made it feel awkward to push the friendships, you know? What might work is for you to start a yahoo group or a meetup group based on your style of homeschooling (maybe a book club for mamas and kids?) Organize a few 'events' and make them structured enough so people want to come, but loose enough to provide space for socializing. At least you then up the odds that your daughter will find someone she has something in common with...someone to play with. Good luck, OP.