New telephoto for trip to Yellowstone

I'm planning a trip to Yellowstone NP this year and thinking about getting an additional lens for some more reach when I'm photographing wildlife. Right now I've got the 18-55 and 55-200 kit lenses for my D5100. I know I'll probably want more than the 55-200 in my bag - but how to get there?? I'm by no means a professional , so although i'd like the best image quality i can get, the chances of me taking the perfect shot are slim. I'd still like my purchase to be something I can grow with from here on out. I'm also on a budget of around $350. Manual mode and focusing doesn't scare me too much - I'll just get better if I need to right? Zoom would probably be the best choice, but not if i can get a better quality lens that fits what I need, right?

What are the pro's/cons of going with the solutions I've come up with below? Are there other solutions I haven't thought of but should??
- I've seen some Nikon 500mm reflex lenses on ebay, as well as the other brands (Rokinon, Bower, Vivitar) I'm assuming the Nikon would have the better image quality, but are the others a reasonable choice considering the reduced price - about half of the cost of the Nikon? Is the Nikon 500mm clearly the best choice for what i want. I read Photowyzard's review of the lens and got some good info off of that. The only negative he had about the lens was that it was difficult (yes, i know about the bokah.)
-Opteka 800mm reflex - I'm assuming this would be harder in terms of focus, etc. If not, is it comparable to the other non-Nikon lenses listed above or junk?
Or something else. I see the following available now. Anything I should be jumping on? Most of these are also zoom lenses too. Would i regret the 200-500mm gap I'd have in my bag if i purchased the Nikon 500mm?
-Tamron 200-400mm f5.6
-Sigma 170-500mm f5-6.3
-Tamron 200-400mm f5.6
-Tamron 200-500mm f5-6.3
-Sigma 400mm 5.6
-Rokinon (and other branded) 650-2600 with 2x teleconverter - not read any good reviews on these. Follow my instincts here and avoid, or am i missing something?
-just get a teleconverter for my 55-200 and call it good.

You are probably better off in renting a decent lens since you don't go to that place that frequent. The Nikon 28-300mm FX lens should take care most of the scenes that you would like to capture.

LensRentals.com - Rent a Nikon 28-300mm f/3.5-5.6G ED AF-S VR

Yep, renting one would certainly get me what I need for much less. But I live in South Dakota - open country. Lot's of opportunities to use higher power telephoto so it will get more use that this trip. I think I'd prefer to skip the rental and start to build up my lens options.

That being said, would you still chose renting the 28-300mm over anything I've listed or in or near my price range? Most of what i've read online suggest at least a 400mm if possible? Is the 300mm too close to my 200mm to be worthwhile?? Or do i just have a case of overkill on my part here?

Thanks

You didn't specify what you wanted to take. Some who shoots birds definitely longer lenses.

I would personally avoid reflex lenses and the use of 2x TC.

Your budget doesn't support your desires but I guess you can go with the Nikon 55-300mm DX lens.

AF-S DX NIKKOR 55-300mm f/4.5-5.6G ED VR from Nikon

Will be photographing the wildlife -hopefully elk, moose, bears, buffalo, yes birds, whatever I see. Yes, budget is tight as i'm also planning on getting a wide angle lens(Tamron 10-24 or Sigma 10-20, or Tokina 11-16) something i've wanted for some time. I was just hoping that one of the other lenses listed above would be good enough to get by with and not be considered a complete wasted purchase when and if i upgrade to a better quality telephoto in the future. Sounds like you are saying to pass on them all. Any other opinions out there?

You might want to double check as the majority of the NP schedules will be impacted by the budget cuts.

Very strange I just tested a sigma 70-300 DG ( full frame) expecting it to be junk and it was as good as the nikon zoom I tested it against and only $200 Thats equivalent to a 450mm if on a DX camera ......cheap nasty plastic but it works ...I would suggest you get a lens with VR ....look at DXO for lens comparisons. Tamron always come out bottom of the pile.