@Jon Q. - I am also working on a first time SS acquisition (as part of a 1031 out of SFR). I am also just getting into SS as an asset class and I think the short answer to your question in my experience is that there is no one source that aggregates SS listings. I found that to be very frustrating as I worked through my search for a deal.
I have a deal in contract right now (50k sf / 300 units) and it took awhile to find anything that worked. I initially was looking for something local through loopnet that I could manage myself alongside my regular (non REI) job. But couldn't find any deals in my local market that made sense. So I expanded my search by contacting brokers who had listings (loopnet, argus, and marcus & millichap) and just telling them what I was looking for and seeing what they had. I finally found a broker I liked working with - Michael Morrison at Midcoast Properties - and we worked together for about 4 months looking at deals across much of the southeast US - he brought me deals to look at as they came to market and I continued to look on my own as well and passed these deals I saw on to him and he contacted the listing brokers on my behalf. By that point I had made the decision to focus on properties that were big enough to justify third-party management, which generally seemed to be about the 40k sf threshold, though some regional companies seem willing to take on smaller properties.
My experience across all the deals I looked at was that most sellers were looking for premiums above what I expected to pay based on market caps. Generally that took the form of facilities that were valuing themselves on proformas that required real value add - whether in the form of management or capital expenditures. I was seeing very little realistic discounting of properties to reflect their current economic performance. Our valuations based on current NOIs were consistently 15-20% less than ask, and our offers got counters that were just marginally less than the original ask. The SS market, as @Michael Wagner suggests, certainly seems to be humming along.
My takeaway from the deals I looked at (mostly in the $2-$5m range) was that I had to be willing to pay a premium above what I thought the properties were currently worth that I could swallow based on the upside we thought we could coax out of it. And we finally found a couple of deals that I was comfortable with. Within my 1031 timeframe, I had to decide whether buying into a deal with a premium was worth it to get my tax deferral, and at the end of the day we found a deal that worked.
As for financing, I'm still working through that. I talked with some big banks directly, some brokers with CMBS and life insurance lenders, and local banks near the property. It seems to me the local banks will be far and away the most competitive option. The bank that currently holds the note on the property wants to keep it and I expect that is where we will end up. They want 20% and will offer a fixed, 25yr term.
Happy to talk more about my experience if you want to contact me...