"The Moonbase", "The Ice Warriors", and "The Invasion" are the only Troughton stories that have been released with animation, I'm afraid. You can watch the LCP reconstructions, though, which use tele-snaps (still photos), surviving clips where possible, and the original audio to reconstruct all the missing episodes. Or if you can find the CDs, there are audio-only soundtracks you can listen to that use the original audio along with linking narration from surviving cast members.
Or, if you're like me and work better with reading than listening, you can "watch" the episodes by reading the
transcripts. That's what I've been doing for the most part, then I go to the recons or Wikipedia only on the rare occasion that there's a scene where I feel like I need extra help understanding what's going on. (Or, more often, for the scenes that I'd simply like to hear as well as read, such as the 2nd Doctor's recorder playing. ^^) There are also novelizations you can find of all the stories, if you prefer that over reading the actual scripts.