Well, I appear to be up and running using Amazon AWS after the DNS change. I’m using W3 Total Cache (W3TC) which minifies, zips and caches Javascript and CSS to Amazon S3. It also copies images there too. I was thinking of adding Cloudfront too, but probably not needed at this time.
I had a couple of glitches. I forgot to update my wp-config.php to update the temporary URL’s that had pointed to my Amazon EC2 instance prior to the DNS change. With that change and a W3TC cache purge things seem to be working ok.
I also changed my WordPress theme to Twenty Sixteen. with only a few changes to make it mostly look like the old site. No custom PHP changes at this time. I like that it’s mobile friendly and responsive, probably good enough for now.
ps. Actually it took a couple of more days for things to settle down. Minifying some of the Javascript broke something, so now it’s mostly just combined and loaded later. Google PageSpeed Insights had a number of suggestions for optimizing the CSS/JS. I could probably spend more time messing around trying to optimize according to PageSpeed, but I did improve a few things. The next step would be to pull out and embed some of the CSS that would let a browser render above the fold without a separate CSS file load.