First, naltrexone will not alleviate withdrawal symptoms, instead it will precipitate them if you are physically dependent. In rapid detoxification protocols usually they put you under anesthesia and administer naltrexone so you quickly go through the withdrawal process... this sounds great in theory but is nearly universally discredited for a large number of reasons (there are threads on this so search around if interested, usually labelled "ultra-rapid opiate detox" UROD or similar terms should produce results).
Naltrexone, either orally or via implant, generally is most beneficial to block (antagonize) the opiate receptors so full agonists will not work. I suppose its *possible* that it will cut the PAWS symptoms shorter by helping your brain get closer to a normal state quicker as far as receptor sites and endorphin production and all that but that is assuming PAWS is purely caused by neurological changes. The general consensus is PAWS is attributed a number of factors from organic changes, damage from drug use and very largely from the psychological effects of chronically using mind-altering chemicals. I usually see PAWS more as the difficulty in transitioning from getting high to having to cope with life on life's terms.
If your main concern is PAWS, I think diet, exercise and counseling will expedite the process and alleviate more symptoms than naltrexone. In fact, I worry that the desire to use naltrexone is simply a manifestation of the problematic mindset that may have led you into drugs... that when something is wrong, simply take some chemicals. If you truly want to move past the drugs in your life, I don't think naltrexone will be your best bet.
If you think the antagonist effect alone will be beneficial to your transition to sober living, then I think it might be worth a shot. I would definitely read around here for people's experience with naltrexone however, because they are overwhelmingly negative.