Well you made it sound like you wanted legit official channels, but yes kissanime has a lot haha. But I think it's just user uploads, so the quality might vary and might not be up to par with the best current releases and all. But yeah that opens up your options a ton. Personally I still download, but I think BakaBT just went private so it might be hard to get in.
For Gundam, you can watch the original movie trilogy if you want for a quicker dissection of it and the pacing is still great. Most fans agree it's not a bad way to go. Or just watch the original 0079 series itself. Just remember, this is ancient Sunrise with some budget constraints, so it does look humorously bad sometimes, but oh well haha.
From there, I actually would not recommend the Zeta trilogy movies, because they have new scenes made in 2005 mixed in, weird musical changes and cuts, etc. It's a choppy bad version.
The Universal Century timeline is the main verse. Check out the Order of Release list here:
http://gundam.wikia.com/wiki/Universal_CenturyRelease date order is always my recommendation for anime! If you want kind of the main storyline from the creator and director Tomino himself, you want to watch:
0079
Zeta
ZZ
Char's Counterrattack
That fully concludes the main arc for the most part. And I think Gundam Unicorn is the next real step after that one.
Granted, some people like the stand alone UC OVA's like 0080 War in the Pocket, 8th MS Team, or 0083. But I think you'd maybe get more out of them if you at least watch 0079 first to get a backdrop of the world.
From there, if you want some stand alone shows, I think Gundam X, G Gundam, and Turn A are pretty good.
I don't really care for Wing, SEED, or 00. They retread all the plotlines you get in the UC stuff, but are just worse in every department. Some people like them. Your mileage will vary. I absolutely love a big chunk for of the Gundam franchise and hate another chunk of it, lol. There's no middle ground for me...
Hope that's not overwhelming.