Welcome active posting,
@lee_brooklyn!
I've not tried the 4x5 mkII Intrepid; I do have an 8x10 mkI and never had any issues with light leaks. It's also the first time I hear of light leak issues involving the back. The mechanism is simple, but appears to work quite well. It is a lightweight camera - which is both good and bad. Good: portable. Bad: flimsy, shaky and more prone to wear & tear than more solid cameras. Every camera is a compromise.
I agree with
@BrianShaw that 5x7 film availability is limited. I honestly think you're better off with 4x5", unless you want to do contact prints from in-camera negatives. In that case 5x7" and larger can be worth the extra hassle. That hassle also translates into bigger everything - bigger lenses, bigger film holders, so more volume + mass to lug around.
If you're bent on 5x7 - sometimes Burke & James cameras pop up here and there. I doubt you'll find a Rittreck 5x7 within your budget esp. if the $1k also has to cover at least one lens and one or two film holders. 4x5" is a different story; film holders are relatively easy to get and not too expensive, plenty of choice in lenses as well as cameras and $1k will buy you a decent kit.
What's your process (scanning, enlargement, contact printing) and intended print size?
How important is agility in composing etc. for you? Keep in mind a view camera is fairly static. It translates in the kind of photos you'll make. For some styles that's fine and not a limitations. It depends.
Any 8x10 users out there who go hiking with their camera?
Sure, but not me and I frankly think it's insane. There will be a few who chime in though.
Evidently, everyone will tell you what they are doing is great and worth it. That's why we do it.
I have both an Intrepid 8x10 and a Sinar Norma 8x10. Neither I consider suitable for hiking. If only for the limited number of captures I could do. So I'd go on a multi-hour hike and be limited to like 4 photos on 8x10? What if I see a fifth image I would have wanted to capture? Smaller formats are just more suitable. Medium format is nice for hiking. Why not keep using that?
You mention planning on doing hikes, cityscapes etc. You must be a masochist to want to do that on large format. Bigger ain't better.
PS: you mention the intimidating cost of shooting 8x10. If you're very cost/price-sensitive, large format may not be the most obvious choice. Having said that, take into consideration the following:
Fomapan 4x5" 50 sheet box ca. $85
Fomapan 5x7" 50 sheet box ca. $125
Fomapan 8x10" 50 sheet box ca. $175
Adorama price point. You're cost-sensitive so you will end up shooting something like Fomapan anyway.