IMO, 4 weeks in the fermenter is too long for an IPA. Keep in mind that hop flavors will be the first flavors to fade. If you do everything right and pitch and ferment at 68, you'll probably be ready to keg/bottle at 2-3 weeks. My IPA/APA fermentation schedule is dryhop on day 7 if fermentation is done and bottle on day 14. Usually it reaches FG by day 4, so I'll dryhop then and bottle after 7 more days.
How is your boil? It doesn't have to be crazy, but if it is not a rolling boil, it could give you issues with hop flavor/bitterness.