Does this vary much by town or is it a state thing?

Buy analyzing 5-10 houses at varying price points from your area, you will quickly determine what dollar per square foot you have to buy at for a deal to be inside your parameters to buy and be able to make money.  

Use varies throughout the year.

YMMV (your mileage may vary)Fixable alone: boiler maintenance and steam system rebalancing, minor lead paint sealing, plaster patching (even very large ones), thermostat installation, insulate flooring and rim joists, painting, floor repair, skim coating walls, installing thresholds, weatherproofing, installing/refinishing door and cabinet hardware, adjuster gutter drainageNeeded professionals: sewage main unclogging ($), knob and tube disconnection+removal ($$), flooring ($$), adding joists for structural support within walls ($$), replacement and removal of old brass/cast iron plumbing where necessary ($$$), new gas line for laundry and lines for appliances ($), wall demo + replacement ($$$), steam line moving and radiator repair ($$), gutters ($$)$ - hundreds, $$ - thousands, $$$ 5K-10K, $$$$ - tens of thousandsHope this helps, best of luck with the old home!

While the units do vary in  rental rate from very low to very high, each individually is very well maintained and very well prepped by the various owners.

Depending on how close you are to the beach/ how many beds etc. your rents vary drastically.  

Break that down further within each state,county, and city throughout the country.Opportunity can be defined a ton of different ways and varies person to person.

BP forums are great, but the answers will vary wildly from post to post :D 

I consider a Hard money lender or DSCR lender as a totally different category.

It is a duplex, not sure of it varies for a SFH.