Dan: you and I have discussed this many times. So yes, I will disagree to some extent. In a perfect world, one gets to do both: a trip like you say, alone or with one other friend, or a trip like Jim is going to do, with a group of friends.
The interesting thing here is I think I'm one of very few who has done both.
And both are indeed fun. Dan's right - going with one other friend, you'll get a much greater sense of the Scottish people, life, etc. You'll meet more Scottish people out of necessity. And in the end that will be a good thing.
But what I think Dan tends to miss is that if one goes with a group, that doesn't necessarily PRECLUDE the same sort of experience - it just makes it a little tougher to do, given you have your own friends with you and thus the inclination might not be to branch out; not to mention the fact that most Scots will see a group of tourists and run the other way.
However, if you are so inclined, you can have this sort of Scottish experience even with a group. It just takes a little effort. I know, I achieved it with a group of 12 last time I went. We met LOTS of Scots, played golf with and against them, drank Belhaven's Best buying lots of it for them (and having it bought for us), stayed at B&B's for the most part and loved all of it. And we achieved this because I drummed into the other guys the proper attitude.
So I am here to say it can be done - this need not be mutually exclusive, as Dan seems to say.
As for the golf courses, I'm gonna heartily disagree with Dan there, and I've made my point already. Sure it's great to get off the beaten track, but it's the road to regret if you don't play the Open courses that fuel your dreams. Only if you are VERY adventurous and/or have an entire summer to spend over there (like Dan did) would I advise playing hidden gems at the expense of the Open greats. Once those have been played and experienced, THEN branch out. As for TOC, having played with locals and with friends, well... sharing it with great friends should not be downgraded. Special places deserve to be shared. Both ways are great though. But man, especially if one only has a short amount of time, to me it's tough to just depend on the lottery there and hope for the best. TOC is a life experience that shouldn't be left to chance - I don't think so anyway - the room for regret there is just too huge.
In the end, as Rich says, there remains no wrong way to do this.
In any case for the folks asking here, the question seems to be moot - each is going with a large group. No way would I advise them to eschew such - it is great fun. I don't think Dan would either - seems that decision has been made.
And if you have a large group, even Dan would have to agree a bus and driver is the way to go. Driving over there is difficult, and until one has experienced how cool that rolling cocktail party can be with great friends, one ought not to knock it.
TH