(About meditating in group):
Well different people have different feelings, but my experience is that I practice better alone. I initially attended "courses" or "retreats". The first ones were inspirational as I saw the behavior of experienced meditators. But now I hardly stand meditating in a group - if it is not in one of those Goenka group sittings, during which people tend to be less lethargic and more focused - and that is because I feel like my neighbors suck my energy, so I feel very tired very soon and I manage to concentrate only poorly.
After all, the Buddha always encourages meditators to go alone in the forest or in an empty room, and I think this is the reason why. It is most probably the reason why someone like Goenka also allows experienced meditators to meditate in individual cells. That said, meditation in group even outside "group sittings" can be beneficial to strengthen the practice if performed for example once weekly.
(About seeking a teacher):
A teacher's job imo is fourfold: 1) ask questions to make sure one practices correctly 2) answer questions so as to eliminate doubts 3) motivate for applying effort 4) create and maintain conducive conditions for the practice.
You may not need a teacher nearby all the time if you can satisfy yourself in these four ways. I agree seeing a teacher can be useful, but it can also be detrimental as some teachers, even widely renowned, may actually teach out of delusion and therefore mislead their followers. So you have to choose very carefully.
There is only one criterion of choice that is very clear to me right now: if you are looking for a monastic teacher, choose one who is perfect in Vinaya, and reject any teacher who involves himself in money transfers. I would even add to choose one who refuses luxury (as the Buddha reportedly refused to walk on a red carpet), but I am afraid that would cut your list down to none.
Where knowledge ends, religion begins. - B. Disraelihttp://www.buddha-vacana.org
As a sweet-smelling and beautiful lotus flower may grow upon a heap of rubbish thrown on the highway, so also, out of the rubbish heap of beings may appear a disciple of the Buddha, who with his wisdom, shines resplendent in wisdom. -/ Dhp 58-59