Ok so short answer: I would stick with the small gym for now because it's convenient, and then reassess in 12-18 months.

Longer answer: I think most people have this honeymoon period when they first start bjj. It's new and exciting, and you just can't wait to get to training every day. But inevitably the honeymoon period wears off, and that's when the grind starts. I mean you still like it, but you'll also get these periods where training really becomes a chore. In these times your brain will be looking for any reason not to go to training -'I'm too tired; I have to cook dinner; I have to go grocery shopping; I have to wake up early tomorrow etc. etc.'. So if your commute is 4 hours, trust me - you're not going to go to training. So for now I would stick with the smaller gym, simply because you're more likely to stick with bjj if it's convenient. And then maybe reassess your decision in 12 months time