To really save money, do not buy the Skyliner but instead the Kyuuko (express) train which also leaves from the same platform. It is only 1,000 yen all the way to Ueno (or Nippori for that matter), and it gets you into Nippori ony about 20 minutes later than the Skyliner. ^ The only downside is that it is a standard subway-type car as opposed to the nicer seats in the Skyliner. But Narita Airport is the beginning of the line (especially if you are picking up the train at Terminal 1), so you will no doubt get a seat.

Tell the agent at the counter what JR station is your final destination and she will issue you two tickets-- one for Keisei railway and the other for JR. Put them both in the entrance gate machine and then again both together once you get up the stairs at Nippori during the transfer to JR. At that point you will only have ONE remaining (the JR ticket), as the Keisei ticket will be taken.

The Nippori transfer is no big deal with one suitcase. Escalators take you upstairs to the entrance gate machines, but you will have to carry the bag down stairs at the JR platform.

Most stations in Tokyo are becoming very friendly for the disabled traveler, so this bodes well for those with rolling suitcases too... elevators are popping up all over the town nowdays

Good luck, and feel free to PM me if you need more detail.