All other things being equal, more units beats fewer units.A four plex gives you three other tenants paying the mortgage, instead of just one.If you're set on a duplex style approach, look for a situation where there are two homes on one lot.

It looks like you have a Net Worth sufficient to do a $300K loan, although the lender may also want to see some more liquidity too.To go bigger, you may need to get a partner that can be a guarantor on the note.  

I would look at what your property manager is doing and whether it is sufficient or not?  

Quote from @James Sloan: What do you all think of this attitude: I would sooner have, hold, pay off, and manage one property well, than many which are average: it is better to do well with one property at a time than to own more than one average properties: you only need one paid-for property to keep personal freedom: when one is not enough, it is time to upscale by trading for another property which sufficiently challenges you.

Open bar and have appetizers at both (Tuesday is more dinner sufficient). 

Besides giving them sufficient notice, is there anything else I should make sure to do?

@Skye Penland - That might work, but my experience with contractors is that those with skills and focus / ethics sufficient that you'd WANT them working on your property - tend to be busy / in high demand.

A good rule of thumb is to make this a requirement in the contract, and get a copy of the endorsement, relying solely on an insurance certificate that states "additional insured" normally isn't sufficient.

It can be rewarding, but it also carries the biggest risk of surprises and delays.Since you mentioned <$200K, you’ll probably come across all three types depending on the market.

@Oscar MiguelThe squatter being in the property is an example of a catalyst for any probate property even for the property your interested in.If the family member, who may become the PR (Personal Representative) knows of the squatter (maybe the family member) and probably wouldn't want to evict.As for the three siblings, there's more than likely adversarial issues between the three as two want to sell (motivated) and one doesn't.Probate is a title problem!!