luceos Thanks! Good suggestions.
last point first, I kind of always felt the same about not hosting at your registrar.
But that .XYZ (or even .ME) is a great suggestion! For only $2.99/year, thats a great investment and I think I'm going to do that! Besides being the best way to really test, I very much dislike the way most shared hosting directory structures seem to work these days. The unlimited sites packages typically make you choose a "main domain" to start, and then make all the "add ons" or sub-domains you want. What I don't like is that they then put all your "main domain" files and directories in your public_html folder, with additional folders for each 'add on" buried in the fray! But if my "main domain" could be something like "mysandbox.xyz" ( already taken sadly) then THAT could be my 'main" domain. And since it would only have a few files for testing along with an INDEX., it makes it much easier to see your real domain folders. Anyway. it certainly will make testing 100% easier. Great idea!
All this came about because enticed by Bluehost's great 3 year deal, I thought I'd give them a try. But unfortunately that company has an awful way of providing a "test" access. They give you a string you can plug into a browser with a name like "boxXXXX.temp.domains/(tilde)yourdomain . That would be fine, but when you try to use it you find that root access links (like a simple <IMG> tag sourced to "/Images/myimg.jpg" will fail. Why? Because "/" does not actually point to your document root! Apparently, as Bluehost is tightly aligned with Wordpress, the WP folks apparently don't mind using a special global search/replace tool to switch every reference to their own domain to the ridiculous "boxXXXX" string. Than when they are happy and ready to go "live", they reverse the process.
Doable? maybe? But I know as a fact that it doesn't have to be done that way. And since I make a habit of referencing everything to root ("/"), trying to do a global search/replace would probably be VERY error prone. And frankly, having to alter all your files to test a site is (IMHO) very bad practice. In fact every tech support person at OTHER companies I've spoken to since then said they do NOT do it that way, and insisted their "temporary" access would still ensure that "/" points to your own document root directory.
So I took my money back. I have my eye on a few other companies that also have good initial deals and better regular prices than my current company (hostmonster). But before I do, I'll definitely get myself a sandbox domain!