You can bring the wires out of the wall anywhere...20' from the panel, or 2" from the panel...then run them on the surface all the way to the panel box.
But any wire that is not buried in a wall, and will be exposed in the garage/workshop, will have to be run in conduit. You can't run sheathed electrical cable in conduit, so you may have to pick up a few feet of insulated wire to finish this job.
You can bring the wire out of the wall, making the transition via a metal box, then use the appropriate couplings/fittings/conduit to bring the conductors to the panel and to enter the panel.
You can install all the conduit and fittings, less the face plate on the metal box. Tie a small piece of cloth to the end of a string and stuff the cloth in one end of the conduit. Put your shop vac nozzle on the other end of the conduit. The vac will pull the cloth/string through, giving you a pull rope to tie to the conductors, allowing you to pull the conductors through the conduit.
If you have too many 90s you can break the run in half and pull the wire halfway each time. There is a conduit lubricator as well, but with your short run you won't need it.
There are limits as to how many conductors you can run in certain sized conduit. It sounds like you only have a few circuits, though.