Now I have my own opinions about how to correctly smoke pork butts,and they do NOT include crock pots, pressure cookers, or microwaves. You can save that stuff for "Betty Crocker, inovative cooking". If you are in a hurry to have genuine BBQ , hire it done or buy it. It's not an On demand type of product. It takes plans and effort to make good Q, starting with the type and quality of meat.I smoke my butts at a higher heat than most as high as 280 at times. Its all about what works for you and what taste you like, and what type of cooker you have.
I will say this though, and this isn't directed at anyone in particular, or meant in a negative manner, but there is no way an over at 170 will produce an internal temp of 200 an any amount of days or weeks. Sorry, aint buyin that!
I would suggest that your oven runs hotter than its dial says.
To the original author, I would suggest taking a day that you can plan on having 10-12 hrs of free time, maybe do some yard work or things around the house too, and fill your smoker to capacity and store and freeze what you can't eat in 3-4 days, then it will be available for the days you want it quick and easy. We all do that alot. fill that baby up. The butts are always better when they are cooking in company.