I would do the top end before anything else on a 125. Get a service manual first if you don't have one.
You may get away with ring(s) only.
Do you have a Micrometer and a dial bore gage? If not a good shop should not charge to check the clearances.
You can check your big end rod bearing while you have the cylinder off.
Do all of the cheap stuff, Repack the linkage and steering head bearings, true your wheels, Take a torque wrench to all the important bolts - Fork tube, Handle bars, All suspension bolts. Remove and clean your brake calipers, Put anti-seize on the threads. Replace the cotter keys on your foot pegs. replace the water pump seal.
That should keep you busy for a while...