While working through my training and ratings up thru CFI, I used to go overseas for my job, 6 months at a time, no opportunity to fly. The only thing you can really do, in general, is try to keep your head in the game, aviation-wise, as best you can.
Any variety of things can help, books, magazines, video/online courses, home computer sims, etc. When using a sim (Xplane, MS202, whatever), try to be disciplined with procedures, checklists, etc., as if in a real plane, doing pattern work, short cross country runs, etc. It's always fun to fly the sim under the Golden Gate Bridge, or barrel roll the 747, but that may not have much practical value.
I don't know about the Sporty's flight review course specifically, but that could be one of many good tools to use. If you're an AOPA member, their Air Safety Institute has a whole series of excellent online courses and quizzes, covering a variety of topics from VFR weather decisions, mountain flying, reading IFR charts, etc. You mentioned starting IFR training in a few months, you could certainly check with your flight school to see what ground training materials they use and get a head start on your studies. (Any instrument flying text or videos would help, but best if it's whatever course your school uses). FAA Instrument Flying Handbook, and Instrument Procedures Handbook are free online. Weather is another area you could spend time on, the FAA's Aviation Weather is available online, or any other "advanced" weather studies would serve you well. The FAA also recently came out with a Runway incursion/ safe taxi online course, those are always good
https://www.runwaysafetysimulator.com/
The main point, is to try to stay engaged in thinking about aviation, so whenever you get back into the plane, with a CFI for your first "tune-up" flights, you're not so far out of the loop that you forgot how to set the altimeter, tune radios, etc.
