Hi Ian, welcome to the tiddlyverse :)
I think if TiddlyRoam is working for you and the way your working, stick with it :) I believe (and I'm sure Dave will correct me if I'm wrong) that Stroll is a development on from TiddlyBlink and does some things differently.
To actually answer your question, a quick and easy way is if you hit the tick button in your wiki to download an HTML copy of it you could then drag that into an empty stroll and see what happens? (MAKE SURE YOU TEST ON A COPY FIRST!!!)
Or do the same thing in reverse! Drag an empty downloaded Stroll into your wiki (MAKE SURE YOU TEST ON A COPY FIRST!!!) and see what happens!
You may, of course, need a more nuanced solution involving advance search, export and /or filters and others move versed in this will I'm sure help out!
(MAKE SURE YOU TEST ON A COPY FIRST!!!) (MAKE SURE YOU TEST ON A COPY FIRST!!!) (MAKE SURE YOU TEST ON A COPY FIRST!!!) (MAKE SURE YOU TEST ON A COPY FIRST!!!)
:D