You'll make $3-4000/mo bumming if you just maxed out your TP's and UTA's.
Depending on your bid seniority and how fast you become a line holder, you could be making $4-5000/mo at year 2 and beyond by flying for a regional and working Guard on some of your days off...if you have the energy, as that is a lot of work (I know from personal experience).
Depends on your family situation and finances how you want to work that.
You will (probably) build time twice as fast going to a regional. However, you'll lengthen your time to upgrade in the Guard by flying more civilian and less mil.
People will say that 121 SIC time will do you no good. 100% false. You already "Check the Box" as Mil Pilot...you need hours however you can get them, and at 3000 TT regardless of Turbine PIC you will start to get looks from majors.
If you are at a busy Guard Unit....I would continue bumming. BUT if yours is like most units and having a very un-happy sequester (cancelling locals, no MPA trips), your interest in regionals is not without merit. You will take a (big) hit on year 1 regional pay, though...might be a good time to deploy (again) and not spend the money that you just took home from this deployment.
I dk where those figures come from. You don't make close to that maxing TPs and UTA as a copilot Lt. I was at a good regional, a great regional back in the day (Comair) I think I came home w about 14k my first year about 26k the second year. To make enough money to live off at a regional is super tough. On reserve or even as a line holding FO. I have had some reserve guard friends go regionals and quickly go on mil leave trying to find ANYTHING to get them out of the regional including deployments and non flying gigs. To pay the bills. It wasn't until recently that I realized how bad regional life was and I am not sure how I made it.
It's definatly a huge reality check coming off Lt bumming tax free etc. again it might be a good back up plan if MPA goes belly up. That's why I got my apps out to Atlas last year. I loved bumming but my days were numbered and owning houses and having a family I couldn't take that chance.
Some regional experience would definatly be beneficial going to a major... I honostly am not sure what i'd do but if the ACMI/LCC's aren't calling you maybe grab an rj gig as a backup! Good luck!