Hi Tim,
Yes, the easiest way is to use a Gantry 5 template with the "OnePage Menu" particle.
You can install the new template on a subdomain or in a subfolder.
There are of course other ways, but they are much more complicated and involve quite a bit of custom coding - load the UIkit v2 framework in the current Gantry 4 template, re-write the whole "OnePage Menu" particle as a Custom HTML module and style is with CSS.