New to Forum & Considering F150 Powerstroke

Hello all - Considering a 2018 F150 Lariat Powerstroke to replace my 2010 F150 Lariat 5.4 with 329,000 miles. I do a great deal of driving as a consultant and sometimes pull a 6'X10' enclosed Car-Mate trailer that weighs about 3,000 lbs. Never owned a diesel and for some unknown reason always wanted one. Love F150 ride and do not really have the need for a 250 or larger. Like the idea of higher MPG...briefly considered a Porsche Cayenne diesel that gets 20 city and 29 highway, but in my business would send the wrong image. Couple of newbie questions:

1. Having not read the owner's manual, which I do (cover to cover) how does one properly break in the motor?

2. So, DEF thing will be new to me. I have heard about "crappy" DEF and it crystalizing. Thoughts?

3. How long should I wait before I tow the trailer? Mileage wise?

4. Most importantly, what am I not asking you guys that I should know? What can shed light on for a new potential owner?

Thanks in advance for information. I am very close to purchasing, but it is a chunk of money for a new truck regardless of setup and I work too hard, as does my truck, to make a bad and uniformed decision.