I did go for a bike fit on my Raleigh and we got it to a comfortable road fit, but there was no way I could get it to fit with tribars as the top tube was a bit to long for me. Also like yours I couldn't get 10 speed cassette in it as the rear forks are too narrow. I did outlaw half on it, but was too slow on the bike for the full.
I went for a ladies roadie with tri bars, best fit geometry wise for me and I can still do sportives on it like Ride London. As for the full distance, I'm yet to find out hope to have another go at Barcelona next year.