Okay, I followed the suggestions, and have tried the following:
First, to 1492.. thanks for that testmy.net link, that works really well! I also found (I think someone here told me about it, but I can't find it now??) an Android app, "Wifi Analyzer" on Google play that is absolutely fantastic!!!!! HIGHLY recommend it if you are having problems or questions about your service!! VERY handy app!!
Now: took the phone, with the "Wifi Analyzer" on, and wandered around inside the fiver and then outside the fiver and then into the Casita where the router is. Basically, the signal is off the chart inside the Casita, but inside the fiver the signal is a pretty poor.
BUT, I also took my laptop and went inside the Casita, had the Netgear wifi dongle to get "N" speeds and went online. Using the "testmy.net" (good link, but watch what you click on, the adverts can be confusing!!) and also "speedtest.net", I found out that the best I could get with the best signal is 1.3mbps DL and .4mbps UL.
Soooo, then I went back outside to the fiver, turned the TP-Link 450mbps wifi card back on, and connected to the router, ran both the testmy.net and speedtest.net tests and found that what I was getting out in the fiver was NO better than inside the Casita.
So, I guess it is what it is. We are tenants, here for the season and I guess we accept it as it is, now that we know it's the service not the equipment.
Many thanks to all for the suggestions and the links, I hope this might help someone else. I was almost ready to start throwing money at repeater/booster equipment until I found out it would serve no purpose.
Still, those two links and that app for the phone are great!! I'll be using those again, likely very frequently as we travel.
Oh yeah, one other thing, kind of irrelevant but may be interesting to someone?? After all the testing, I disconnected from the Casita router and turned my phone hotspot on and connected and re-ran the tests with testmy.net and speedtest.net. W O W !! 10.x download and upload!! Verizon, 4G LTE for those who care, fast, but expensive if you're going to be doing a lot of surfing, just sayin'!
