I do mine in parts. Once midnight (GMT) rolls around, I'll do my dailies, maybe hit a raid and then do half of GW. I know some late end nodes might take a while to get around so I leave the other half until I feel I have time for it.
150 completions and level 85 gets you the ability to sim it. I have 62 more to go, so that's a shade over two months, assuming I can beat it everyday which is increasingly unlikely for a bit until I get my Empire team fully operational. Loads of Zalpatines about currently.
This is easy mode GW I think too. I can only imagine the horror of OG GW.