I’ve just turned my crosser over to road riding as I’ll be getting a new one for next year.
Anyway all I’ve done is slap some good road tyres on it, and the ride is absolutely fine. So I started to think about all the questions about gearing, tyres and what bikes best road or cross.
The set up I’ve ended up with is almost a perfect do it all bike. The Pearson which is the same as a Zepnat gives a nod to road geometry and it takes proper guards as well as two bottles.
The old nine speed 105 and FSA Gossamer compact running gear is ideal for almost anything, general road use, sportives, cross racing and rough stuff rides.
Though in reality all you need to do is change tyres to change the whole bike.
Also this type of frame and others like it i.e Crosslights I think are a bit more handy than some of the micro brand jobs, in the fact that they’re light enough to press on with on the road and more than capable off road including proper racing.
Just wittering, but I know this subject comes up a lot.
Edit; Also I used Eggbeaters and average mountainbike shoes, which were fine with the compact gearing. Again get some stiffer off road shoes and they’d be ideal on road as well as top dollar on your mountainbike.

I use stiff mtb shoes and single sided road SPDs and I find them work fine. Never tried big road cleats, and don’t want to spend loads on new shoes and pedals for a bike I hardly ride anyway.

Re tyres; when I first built up my road bike, I had 18mm tyres on it (from a donor bike). Fast, oh yes. Stupidly fast. Anything more than a few miles was torture though. Got 25c ones on it now, far comfier. I’m not trying to win the TDF.

I’m going to put my money into some stiffer MTB shoes.
Today was the first time (I think) I’ve used compact on the road. TBH it was quite nice, but I found myself mostly using the 50, the drop from 50 to 34 was awful…okay whilst I was on my own, but it’s not a smooth transition.