1. Late to the party, but I use these mushroom-cap brushes chucked into a Dremel to clean wheels and pick-up rollers. They are available on the bay and make quick work of it.
2. Try using an electrically conductive lubricant (like made by Bachman) to oil the pick-up rollers.
3. Definitely tie the outside rails together (Fastrack already does this).
4. Get an inexpensive digital voltmeter and test all around the track to see where there are any spots where the voltage is low. Check for good connectivity of the track sections if there are any and consider adding a feeder and then re-check with the dvm.
5. Buy a track cleaning car (I like the one from Northeast Trains in Peabody, MA) and run it once a month to keep the track clean.
