My two cents (maybe three since I'm in it to win it)...
I was a Guard bubba (C-130 Slick Nav) and took a VLPAD 3 year tour (started July 2017) as a AFROTC Det CC. I had about 15 years total AD time when I started the tour so the long game was to get to the 20 year AD retirement. When the FY18 AvB Expanded Program was announced, I put in some questions to AFPC along the lines of "Hey, I'll sign a five year bonus if you just put me on AD and you can send me to whereveristan after my ROTC tour ends" to which I heard what amounts to crickets. Therefore, I believe AFPC currently has no program for anyone to go onto AD indefinitely from the ANG/AFRC. However, I wouldn't be surprised if they are considering it. So, it could open up anytime I suppose. During my AWC via correspondence course, one of the facilitators told me that is what got him to AD retirement (Reserve to Indef AD). Back to the Bonus issue for those scorekeeping at home, they gave me the bonus anyway until the end of the VLPAD tour. Yes, they gave me a bonus for doing what I was already committed to anyway (and for a rated position which actually no longer exists on active duty). I guess you could say I got a bonus for all those "Nav Bonus" jokes I got to listen to for all those years.
For the original question, I recommend taking the VLPAD tour if they will give it to you and just consider yourself a "Free Agent" going forward. From where I sit on this VLPAD tour, I can start "negotiating" my next VLPAD tour about a year out from the end of this one assuming the program is still open. Yeah, no guarantees but I definitely hold the cards on the next assignment. If I don't like what they offer, I'll just go back into the AFRC/ANG. To be honest, is that all that bad? Cheers!