Well, the audio from the Japanese broadcasts were not english, you would need to sync the DVD audio to them.
I can easily find the synced tracks for you and they should be under 400 days old on usenet
I think there are only 3 instances where any hardcoded subs show in the image, the rest were in the black bars of the broadcast which I removed in my encode.
1 in Raiders at the beginning where it says 'South America 1936'
1 in Temple at the beginning where it says 'Shanghai'
1 in Crusade where Indy and Connery look at the signs pointing to Berlin after the motorcycle scene.
I think that was all of them that I noticed when I watched them recently, so you shouldnt have alot of work to do there. I had a bit of trouble trying to find the right IVTC method though for the encode, but I am sure you could easily figure it out.
Good luck with the project.