Twenty's are hellishly strong bikes and with 20 inch wheels can carry more and take more abuse than a conventional touring bike.
The most crucial changes one needs to make is to change out the wheels for alloy versions and at the very least, change the front wheel... they have some of the poorest wet braking of any bikes which stems from long reach calipers, steel rims, and a very high rolling speed on those wheels.
My fixed Twenty was down to 27 pounds before I pout the fenders back on and added the new Brook's saddle and when I replace the fork and get an alloy stem and bars I should be able to bring to back to that lower weight although it is by no means weighty.
I can also see it as being a decent tourer.