I know it is not advised to ride solo but the guy I ride with bailed on me indefinitely, but will they allow solo riders?

yes for solo riders, but depending on trails chosen (expert), may not be the best choice. But you will always find other riders not far behind

Yes they will....the chances of riding without seeing anyone else is slim

If you go on the weekend there are always riders out there if a problem comes up to help you out

Yes they allow solo riders