I think the most important part of picking which group to go with is what you are looking for? Allow me to play devil's advocate for a moment >
The larger group that has been around a while and has 200+ investigations would probably afford more opportunities to do investigations, but sounds like attending meetings may be more difficult due to distance. On the other hand the smaller group is closer to your location which may make it more convenient to attend meetings and a higher probability of getting more established with the group but, the case load may be few and far between.
Not sure if that helps any but if I were you go with your what your heart says.