Back on the site after a long, multi-year hiatus (spent doing consulting work vs RE investing; now I'm back at it). 

Disclaimer: This is based on adding a door in a single-family home in Missouri; the requirements for multi-family and in other jurisdictions are probably different.If you have any electrical outlet boxes in the fire-rated wall, they probably need to be steel, or the fancier plastic ones... the cheap blue ones aren't rated for it.If you have to bring a pipe through the fire wall, there may be some requirements about that.  

Here are some recommendations for you:Find and connect with other BP members that are in your area:http://www.biggerpockets.com/meetSet up keyword alerts to be notified of the topics that interest you:http://www.biggerpockets.com/alertsRead Beginner’s Guide: http://www.biggerpockets.com/real-estate-investingCheck out BP Podcasts:http://www.biggerpockets.com/renewsblog/category/podcast/If you wish to tag someone in the conversation on the forum, type @ followed by their name and then select the name of that person which should appear below the comments box.

Originally, I started trying to get a license in California because I lived there, but the class I was in for Principles and Practices ended up being the worst possible class ever because the teacher was completely useless (he literally spent 99% of the time talking about how great it was to be a broker and how he's a broker in 3 states and how most of us would fail at being a real estate professional).

I would emphasize stopping source of humidity plus the use of a good dehu, not one from the big-box stores. 

I"ve spent time building a foundation of knowledge on the local markets in PBC and am now actively seeking my first rental property

In box me.Good luck!

I've spent some time there (not much in the past year), and know the landscape changes quickly, of course the same is true in both Philadelphia and Baltimore. 

Do I need to get a PO Box or should I just not have a return address listed?

@Tim Johnson when you're looking to tag someone in a post create the "@" symbol and then start typing the person's name and then underneath the reply box you should see their name pop up and you can click the person you intend to tag.