At present, I have both my mother and myself on my reservation for all 7 nights; however, my mother will not arrive until 5 nights into my stay. Will I have any problems checking in without her (I'm an adult)?
You are both staying in the same room? And you are both registered in that room? Then you won't have any problem. I've even checked in my in-laws before they arrived so they wouldn't have to deal with the front desk stuff.
The only time there has been a problem is when people are checking in with free dining. For free dining reservations, everyone had to be present to make sure people weren't inventing children to get extra dining credits (since it didn't cost extra for the room to add children) and then giving those credits to adults (a loophole Disney has closed). Otherwise, it's no problem. It's easier if you are listed as the primary guest on the reservation, with your mom as the secondary guest.
