So when I am analyzing potential deals, if I am understanding correctly, likely my very first way of filtering out ones NOT worth investigating would be to compare the asking price to what the approximate value is on Zillow? 

Yes, that sounds like a potential scenario as well.We've been quoted 5K for fence repairs that were ultimately fixed for $700 after questioning the extent of damage and further investigation of the cause.

Depending on which of those you choose, you'll then do more investigating into areas, budgets, etc.If you want to do your own rehabs, that's a pretty major undertaking that requires a lot of planning and networking and negotiating.

My investigation found the deed into the Insured had been forged and the actual owner didn't want to sell it. 

I am at the investigating stage and learning about the options.

Finally, do use a tank contractor to investigate a home UST but instead an environmental consultant who understands the UST rules and regulations of the particular state.I have a number of articles about cases involving home heating tanks on my website: www.environmental-law.net if you want more info.

We are investigating smaller, less expensive options.I have also checked with the HM lenders.

Read the fine print on anything where it seems you're getting something for nothing.Years ago I investigated "free" money being offered for lead paint abatement work, and buried many pages into the agreement was a paragraph saying that rents would be kept at least 30% below "fair market rent" for the units for five years, or something to that effect.When I reached that paragraph I stopped reading, it wasn't worth it to continue.Sometimes it's worth the trade-off or restrictions.

Hi Guys,I've only ever bought duplexes, and I am now looking to scale my portfolio.I am investigating two deals, a 4plex vs 14plex.

You need to discuss with a title agency an/or attorney to investigate this particular property.