I have wheeled 2 IFS rigs over the last 10 years. The first was a 91 Toy truck and the second a 92 Runner. I learned on the 91 and refined what I learned on the 92 Runner. I went all over the place in the last 10 years, VA, WVA, Pennsylvania, Paragon, Tellico, Moab, Pismo, and various other places in So.Cal. All with a IFS rigs never anything bigger than 32" tires, no sway bars, strong bumpers, 1 rear locker, and the willingness to take a little body damage. I have had a total blast, the Runner did things I could not believe an IFS truck would do.
You just can't do everything an SAS truck does or at least you can't take the same line.
My point is you have to learn your truck and how to wheel. If you got an IFS truck then lock the rear and add some protection. Then go have a blast. You'll know when it is time to SAS your rig, until then save your money and just have fun.
I say this because I have just sold my 92 Runner and am starting to SAS my 3rd rig an 88 4Runner. I feel after 10 years of wheeling that I am now ready to take the next step. It is a learning curve.
I hate to see someone build an awesome rig and then go out and roll it because they have not "learned" the vehicle or how to wheel yet.
Be safe, wheel what you got, make small upgrades as you go, and plan on a strong foundation in the school of hard knocks !!!