I'll second what Alex said. In the early days of my site, it was primarily from my research and what I -- umm, cribbed, shall we say

-- from other sites (Casey, Joel, Mike, Andy Fields, etc) plus the excellent stuff from m.t.r in those days. I was poor in crediting things other than my sources page. Over time, I acquired more reliable sources but didn't always cite things from my research. These days I'm citing up the wazoo (and that's painful

). What I'm not doing is ensuring those citation links remain valid. I am sure loads of links throughout my site have gone stale; my current editor doesn't make checking stale links easy. Plus, so many road sites have disappeared....
I'll note that one thing I have done on my site is not include opinion, but that doesn't mean there aren't actual errors or incomplete research. I fix them as they are pointed out to me. In the last batch, I know I fixed a long standing error on Route 24 (Ashby meeting Broadway).
Daniel