I have used 4X5 for about 20 years. If I were doing what you are contemplating all over again, I would begin with the decision on the lens focal lengths that I normally used in 35 mm or med format. The lens focal lengths on 4X5 are triple the equivalent focal lengths in 35 mm.
From that decision, I would then choose the camera bellows extension and bellows configuration the best afforded the lens selection.
For instance if you are more inclined to wide angle 28 mm in 35 mm then the equivalent 4X5 lens would be 90 mm. This lens will normally require a bag bellows if one uses movements. The use of rise and tilt, for instance, would be very limited with standard bellows. Does the camera that you are considering have the capability of interchangeable bellows?
On the other hand if you have a telephoto preference. If, for instance, you use a 105 mm in 35 mm then the nearest equivalent lens on 4X5 would be a 305mm. Does the camera that you are considering have sufficient bellows extension to accomodate such a lens? Fifteen inches would be needed for usage other the infinity with that focal length and an 18 inch extension would be preferable.
For landscape photography the single most important camera movement is tilt, both front and rear. Next would be rise/fall. Last would be swing with rear swing being more important the front swing. However swing on both standards is nice to have. The next question to be answered in regard to tilt movements is whether you want base or axis tilt. These are not the same and will have different effects. I prefer base tilt on the rear standard and both axis and base tilt on the front standard.
If you don't want to use Ebay then I can highly recommend Midwest Photo in Columbus, Ohio. Good people, fair prices, and outstanding service. If you want a new camera the I would suggest Canham, Wisner, Zone VI.
Good luck and have fun.