I think the best advice is to see what works for others there.
We use to use two phones on different systems hoping to get service from at least one while out and about. My original Cricket phone that roamed on Verizon was nearly useless up in the hills, Honeys T mobile (roams on AT&T) was functional but just barely.
last year Cricket was bought by AT&T and I had to get a new phone. Wow what a difference it made. up in the hills it works nearly as fast as it does here in town. The web loads at normal speeds and we can even stream if needed. After a month Honey dumped T mobile and got a Cricket phone too. The best part is that for $55 a month, it is pretty much unlimited everything. Even with Honey downloading music videos a lot we haven't come close to the slow down point of our data plans.