Brian, you having shot cf for awhile while, will be depressed by the in-expensive route ( which quickly becomes pricy as you may well know).
I would suggest a TM 1000 by RAW ( they have a web sight) if you want to be serious about it from day one, The marauder to get feet wet,but the CZ 200 better choice.
Bulk fill Tank will run about 250 or more at local dive shop, where you can get it filled also. ( if you get the tank from them , then they will fill it for you) another $200 or so for connection fittings and gauge. Hand pumping gets old real quick ( they cost a couple c notes as well). you are working with 3000 psi air here not a garage compressor. ( as always support equipment is the other 1/2 of the equation)
As to your 124, the piston seal has dried out or gone bad ( early ones were leather, later versions were synthetic) so it likely will need a new piston seal. not something to be fooling with on your own as the piston spring is always under compression even when not cocked. Go the the Yellow forum to find various people who offer repair service. There is a market for those although I do not follow it.
The good news is it is a hoot, and ya can get pellets. Hoarding and/or Govt. intrusion hasn't hit air rifles yet, at least in my area. Got to love the $.02 or less per shot vs our powder burners nowdays. Boy will it teach you to read wind and lighting conditions that you never new existed.
PS sightron or weaver 36x work real well for this