Access local USB devices from a remote PC via remote desktop?

Yes and no.

If you are talking about USB flash drives, it is possible and share them as a hard drive.

The same goes with a few compatible Plug and Play devices, but not everything.

Open remote desktop (Mstsc) and click the "Local Resources" tab, then click "More" under the "Local devices and resources" section.

From here, you should be able to set what is shared from your local machine to the remote.