someone in road asked a similar question about modernising a bike. here is my reply which might be relevant here too. Note i did not have a freewheel. i had a freehub and cassette as you will need for 10 speed.
i upgraded my 7 speed downtube shifting steel bike from early 90's last year to 10 speed shimano 105. I didn't need to increase the spacing on the rear as it was 130 already. I bought the necessary parts gradually and only if what i had was incompatible after trying. By the end of the process this was what i had to get/change.
1) STI shifters
2) cable stops with adjusting barrels to go on the bosses where the downtube shifters are
3) New 10 speed compatible wheels (you only really need a new freehub body but then you will need to redish the wheel, but my old wheels were coming close to needing replacing anyway and i don't have a truing stand. if you do this i suggest leaving this bit to lbs).
4) cassette
5) Front derailleur. You probably don't need to change this. All the advice i read said i shouldn't need to but i found my rx100 fd was designed differently from modern fds. mine had an angle so some of the cable pull translated into a backward movement so the full push of the sti was not all translated into the same amount of lateral movement
6) rear derailleur. You probably don't need to do this but my rx100 did not have a range of movement to reach all 10 cogs. It was just one cog short
7) chain. needed the narrower 10 speed chain
my crankset worked fine. shifted clean as a whistle
Last edited by coasting; 01-26-09 at 06:04 PM.