also does anyone suggest drinking half a cup of cranberry juice a day to keep my digestive system and urinary tract clean?

Look up supplements to keep your gut in check, probiotic foods are best, ones you make yourself are more potent than pasteurized grocery store versions.
Consume bone broths, fermented foods, look up about how to make sauerkraut and milk kefir.
Avoid consuming vitamin A high foods as Accutane is already a mega dose of it, so be very wary of multivitamins also.
Be careful with accutane though, haven't touched the stuff personally.
Look into the gaps diet, ready up about milk thistle for liver health (not sure if its suitable during a course of accutane though).
Cranberry juice should be OK as long as fruit doesn't break you out, try get ones with no added sugar or make your own

hope this helps!