For the best range I think your best bet would be to get some old school 4W CB radios operating at 27MHz if possible. You’ll get less range with the FRS/GMRS radios, even though they output roughly the same power (0.5W for FRS and up to 4W for GMRS in Canada I believe).
A friend bought me a set of the Motorola radios from MEC. They are the larger of the Motorolas that they sell, they’re grey. I’ll try to find mine and give you the model numbers. I do know that they cost her about $160. I used them for two seasons mushroom picking on the Queen Charlotte Islands in northern BC. They worked great. Range was much better than I thought it would be….even through the thick, thick bush. Believe me, they got wet…….very wet. Never a problem.