I probably should know how to do this from high school math but......
Is there a rough estimate of distance from an indoor workout?
I know: RPM, time, wheel (700).
"700" is a type, not a measurement.
You could calculate this, but it won't really matter. I would ask: how do you know RPM (I assume cadence) w/o knowing speed? Speed x time = distance. Thankfully my cadence/spedometer is rear-mounted, so it works on my Road Machine. With that, there's an approximate power curve, so a speed to power translation, within reason, is possible.
It would be much more useful to approximate how much power you put out, or use a HR monitor. The speed you work at indoors will probably not translate to the speed you do outside.
Maybe a different question then.... now that I have moved indoors to trainer, how do a equate my workout to what I do on the road? I guess limiting my perspective to miles is no the way the continue. I do no have a power tap.