So every tenant wants new appliances, new cabinets, new flooring, etc but if your rents are already at market levels then this would not be beneficial to you.

Your mortgage/financing is a whole separate consideration.Back to your properties, it sounds like they are older and would likely need a little more maintenance than your average home (appliances, plumbing, electrical, etc).

This tenant would gladly look past stainless steel appliances if it meant being within 3 minutes of a train station.

As a landlord - I have to say appliances have become one of the biggest headaches.  

All the appliances are working.

This includes new water heater, new furnace, new AC, and updated paint, appliances and flooring, and updating the electric service.

So, make sure that you're certain you have the power capabilities (have you done load calcs across all electric appliances/motors?)...

I'll be starting a first flip very soon, but I seem to be lost at the moment when it comes to finding the right appliances, materials for the interior (i.e., flooring, crown molding, etc.), if needed, which A/C unit to buy, and basically everything else.

The days of stainless steel appliances and Formica counter tops are so last cycle.Now remember, you as a real estate investor are in the Employment Agency arena and it is your agenda to accept bids plans and estimates from several contractors and continue nurturing and cultivating that sphere for your success as an investor.

Check out what appliance specialty stores in your area have to offer.