If Arbeia is closed (make sure, because it's well worth dropping by), start at Wallsend, and make sure you get to see the reproduction military Bath-house, and wall (across the main road).
If you're in a car, and you have a spare hour, have a look at the Vallum crossing and temple in Benwell, and maybe even the turret at Denton.
The stretch of curtain wall at Hedon on the Wall is worth a look if passing.
Again, if you're in a car, park up beside the access to Brunton Turret (tallest surviving turret), and have a look, and then walk (you'll need nearly on hour for this in total) around to the bridge footings at Chesters (assuming you didn't do this when you visited last time - few people do).
If you're willing to walk a mile or two, you can park up at Greencarts crossroads and walk west to the Blackcarts turret (again, less than an hour there and back.)
From Housesteads, walking west as far as Steel Rigg (or even Cawfileds Craggs) you're getting the best scenery and remains along the whole wall. If you really know your onions, you can walk much of it along the fairly flat Military Way, but then you lose the views, and have to know when to divert to the main path to see the remians.) You can then catch the AD123 bus back (or park up at one end, catch the bus, and walk back to your car.)
If you fancy an evening stroll from Corbridge, wander along the south bank of the river from the car park to see the bridge footings (about an hour).
Another well worth while bus stretch is from Greenhead (or Gilsland depending on the bus) to Birdoswald, taking in Poltross Burn Milecastle. Some excellent remains on that stretch.
On the way back from Birdoswald, don't forget Pike Hill Signal tower and Bankshead Turret. Also, much missed by the tourists id the curtain wall stretch at Hare Hill (just west of Banks). Last, and tallest remaining stretch.
The only thing I'd recomend beyond that is Tullie House Museum in Carlisle itself. Very good museum with a newly opened Roman Gallery.
Feel free to PM me for details.