My wife and I bought this a year ago for our 3 kids, ages between 5 and 8. We spent about 30 hours assembling (60 man hours) and are moderately skilled.  Instructions are straight forward, all parts included. Some of the biggest time consuming was digging through boxes looking for specific pieces of wood. The boxes are pretty heavy (there were 4 for us) so drop it as close as you can to where you plan to work. The first 5 or 6 hours were assembling things relatively small so we were able to do this in our garage. Was able to use a tall bar stool instead of a step ladder.  Only fought once which is better than normal for projects for us, so would consider this low stress.