+1 to a second room. I am having more trouble falling and staying asleep these days, and my husband is a snorer--not severe (ie not sleep apnea pattern, which your Mom sounds like she could be), but enough that I can't cope and sleep with him much of the time. I shelled out the $150 for custom-fitted silicone earplugs, which are awesome and go a *long* way, but not all the way. Apparently low frequencies are the hardest to block, and of course, much of snoring is that low rumble. :(
So, I can get by with the earplugs maybe 80% of the time, but some nights one or the other of us ends up in the other room. In your shoes, I'd just plan for the second room and enjoy the trip rather than being crazy, tired, and resentful. I realized through this process that a good night's sleep = a happy relationship! :)