For payments etc you will need to show them proof of ownership and coordinate with them where to send payments, how do they make maintenance requests and emergency numbers etc

Over leveraging is a real thing and you don't want to be caught without a decent emergency fund because you tried to start running before walking.

If I paid someone a reasonable salary (I'm thinking $1,000/month) and they managed both properties in terms of guest communication, responding to emergencies when they appear, visit the properties (they're next door to eachother) weekly, and have a monthly meeting with me to brief me on what's going on (or someother regular timeframe).

The biggest thing is where to park it - many jurisdictions restrict or prevent them altogether, but a few have emerged as "friendly" tiny house areas - do a google search. 

It's only after the 3rd occurrence over July 4th weekend that the PM told us about any of this.Our new plan is to show up mid-morning on Monday under a lease clause that we can enter the property without notice to: 1) survey or review the Property condition; (2) make emergency repairs; (3) exercise a contractual or statutory lien; (4) leave written notices; which we'll be doing both 1 & 4.

If you can push it to 600-800K which you said, you need to make sure that if an emergency arises, you still have money to cover it.You could also look at some out of town places if the prices and numbers are better in another area.

@Nicholas JacksonI think you can look into other emerging markets for the multifamily deal that fits in your criteria.Also you can use value add investment strategy, where multifamily real estate investors will purchase a value add property at a discounted price and later sell the asset in a much better condition.

do you have money for a down payment, reserves, and a personal emergency fund?

Assuming there is demand, I would discuss with county and local fire marshals, city planning admin, county engineering, county floodplain, zoning.... how are you getting utilities, are there impact fees associated with them (water / sewer / electricity), assuming it's a state owned road you are on, you will have to get a permit from them as well (Ask your civil engineering company about this), Do you have a survey, does it have topo, what are your setbacks from the road, if it's a large road it may be significant if there is expansion planned, Does it have the required ingress / egress for emergency vehicles (ie. min road widths and entrances), does it have appropriate water supply for the latest fire codes (ask your civil engineering company for references to fire engineers or if they have somebody in staff that can help), where do you need fire hydrants and are sprinklers required, are there any easements currently- will you need to grant any for utilities... 

They typically fail in August at the worst time and you will pay a fortune for an emergency replacement