I literally told them (Sparklight) the service was for the building and had no difficulties obtaining this.I can see the day when there will no longer be USPS; by their own inflexibility to serve others and move toward the changing postal needs and desires of people, they have set in motion their obsolescence.

It's far less comfortable day to day having roommates vs your own side of a duplex, but it would allow you to own an asset in a more desirable neighborhood that will likely see greater appreciation over the long term.I hope that helps.

I am looking for an agent who has experience with working with investors and who knows the area well (rents, desirable areas vs. undesirable areas, etc).

This strategy aligns well with your desire to build equity quickly and transition to rentals.

It's impossible to know everything about a market, so any value add information is expressly desired, and I appreciate it!

Should I be looking in less desireable neighborhoods?

I'd warn anyone pursuing this that it is VERY difficult to find land zoned for manufactured houses, especially in a desirable location. 

It's in a desirable low vacancy, high demand location that happens to be in a mixed commercial / residential semi-neglected but very safe area 2 blocks off a major shopping street. 

Share the details of your project as much as possible and let them know how much involvement and communication you desire from that person. 

The houses are close to zero cash flow after accounting for expenses, but they are desirable areas.