At our first birth, we had one of Victoria's friends as a support person. She was lovely, very helpful, and not too intrusive. We couldn't thank her enough. Shortly after the birth, we had also invited one of our midwives' daughters, who was a photographger with whom we'd become friends, to come in and take photographs.
At our second birth, we had Victoria's mother. In hindsight, I think we had her there more for her needs (she had never seen a birth before, and really wanted to be there) than our own, and while she was not unhelpful, she wasn't as intuitve as Victoria's friend had been; I think this is reflected in the fact that Victoria's friend had always intended to be there fully for us, whereas her mother wanted to be there for her own experience as much as ours.
So, in answer, I felt we had the right number of people at our first birth, but perhaps that we could have been just the two of us and our midwife at the second. Having said that, our opinion might have been different of Molly had been awake during the birth as Victoria's mother would have been looking after her!
As far as keeping people away, we just took the phone off the hook and didn't tell anyone it was happening until after the birth. And in the days after the birth, we were quite upfront when we didn;t want visitors. Most people understand, and if you have a helpful midwife, they may be happy to talk to family members and gently remind them that "visiting hours" still apply at a home birth!
Midwives offer non-pharmacological pain relief. That means mild pain relief, such as over the counter paracetamol and similar pain relievers, massage, water, homeopathics, and the like. Some midwives will offer transcutaneous electrical nerve stimulation machines (TENS) or you can hire your own. Sterile Water Injections (SWI) are a fairly new practice that can also be used at home to reduce pain. And rarely, with the assistance of a GP, it is possible to hire an entonox machine (nitrous oxide, or "gas") to be used at home. As many midwives will warn you, though, using artificial forms of pain relief inhibits the body's own pain relief mechanisms, and paradoxically, some women find that they cope better in established labour without pain relief, as their body will produce it's own endorphins.

