Be a long-term investor focusing on controlling as many assets as possible most safely. 

NYC laws around rentals—especially short- to mid-term—can be tricky, so you’ll want to avoid any compliance headaches.The biggest challenge with this plan is finding a rent-stabilized apartment that makes financial sense and actually gives you breathing room.

Over time, I’ve accumulated more cash reserves and don’t need as much flexibility, but I’m actually in the middle of a refinance right now using an interest-only mortgage—because the pricing with the lender and the corresponding ARM is more favorable than a comparable principal-and-interest loan.The key with these alternative or "exotic" mortgage types is that you need to be financially savvy and have a solid plan.

Let's assume that the neighborhood is a C class and the median income of the city is greater than 3X of the market rent.Here are some of the considerations I've come up with so far:- Units are in need of renovation and capex is too high or not available- Unit quality is not the same as market - Seller is worried about losing tenants due to increase- Vacancy rates are high or filling units have been difficult- Rent increase would take multiple increases over multiple lease periods to get to market rate if seller is trying to retain the same tenant- Seller inherited property and just want to liquidate- Seller needs to liquidate quickly (financial burden, sickness, quick exit from land-lording)It seems like I might be missing a warning sign about a deal if they are selling with current rents that are under market; but again, this seems to be most of the properties I've underwritten.And in the same vein, what should I be worried about when purchasing a deal with under market rent with the intention of raising them after purchase. 

And while I agree that debt is often the cheapest form of capital, if you are looking at a project that involves some form of value-add business plan, you can always refi either when rates come down or you have increased the yield on the asset to exceed your interest rate.But like Stuart noted, for many groups, even the most seasoned syndicators, raising call cash for their deals is effectively impossible.  

You need to look at all the financial numbers of the business/ hotel and owners won't release them until there is a contract in place.

Tenant issues are more likely to arise and then you have the owner....many aren't qualified expertise wise or financially to weather the storm.

A couple of things I like to tell my newbies-Owning a short-term rental property can offer significant financial benefits.

You hit the nail on the head...that's where the SFH to Duplex conversion gets financially unrealistic.

-------------------------------------------------------------------Recommend you first figure out the property Class you want to invest in, THEN figure out the corresponding location to invest in.Property Class will typically dictate the Class of tenant you get, which greatly IMPACTS rental income stability and property maintenance/damage by tenants.If you apply Class A assumptions to a Class B or C purchase, your expectations won’t be met and it may be a financial disaster.If you buy/renovate a property in Class D area to Class A standards, what quality of tenant will you get?