There is a huge difference in the style of photography between a DSLR and a 4x5 field or view camera. I would take a very serious look at how you'll be using the camera. Like Hertz said, manual exposure (shutter and aperture) is pretty much the same on any camera. The large format camera is going to be big and heavy and cumbersome compared to a DSLR. Most folks will never use their 4x5 cameras handheld, so a tripod is a must. With large format the act of photography is a much slower, thought out process; too much so for many subjects (like almost anything that moves

). A DSLR would probably be an overall more functional camera due to it's flexibility of use, but landscapes from large format film are pretty awesome. LF cameras are usually
all manual, and I don't mean just exposure. You have to remember to do a lot of things that even roll film cameras we call fully manual do for you automatically.
If you aren't going to process your own film then you'll need to find a lab that handles 4x5 processing. It's not hard to find places that can scan sheet film, and print from it, but developing is another thing. On the other hand, do it yourself! BW would be easier, but there are people doing their own C-41 and E6 processing and printing.
Don't worry about the cost if you think you would be interested in learning large format film. All photography is expensive; no matter what format or image capturing type. It's going to cost you alot if it turns out you're into it.

Besides, what does a D-70 cost? How about the computer, printer, ink, paper, memory, batteries, and other accessories?
You can get a Speed Graphic 4x5 press camera with a slightly wide angle press lens for under $200. This is the other stuff you'd need to shoot BW landscapes with it:
sturdy tripod ($150-200)
film holders ($5-$10 each, at least 4 to start with)
dark cloth (make it your self for $cheap)
cable release ($10)
lens hood ($5)
light meter ($75-$300)
ISO 400 4x5 film ($40 for 100 sheets at Freestyle^, that's $1.60 for 80 square inches of film. 80 square inches of film costs 2 or 3 times that in 35mm or 120)
a backpack to haul it all in ($20)
If you can find a deal on a tripod, and get a cheaper light meter, a 4x5 BW landscape rig can cost less than $600. If a D-70 plus accessories cost $1300, then you still have $700 left over for a BW darkroom, and maybe a fancier lens.
Ebay is filled with darkroom set-ups and 4x5 enlargers, and they're going dirt cheap. I set up my 4x5 BW darkroom for under $400, and I did it years ago before used darkroom equipment flooded the market. Of course, shipping an enlarger across the country could get expensive.
Medium format can also be had for very cheap. The popular brand prices are dropping like rocks. This makes the less popular brands even a better deal. You can get an excellent Bronica SLR for a steal these days. Older cameras such as the Norita 6x6 SLR are super cheap. Medium format TLRs run $75 to $750 depending on quality and collectability. There are other vintage medium format options. Medium format film is still easy to get processed at labs almost everywhere. Some medium format cameras are more hand holdable than other. Medium format photography is a lot more like 35mm photography than large format; it's just bigger gear and bigger film. Many of the features you find on modern medium format cameras are the same as you'd find on 35mm SLRs, and even DSLRs.
Most LF photographers can't even pronounce "Scheimpflug", and I'm positive that my LF cameras have never even heard of him

I've found that with a little practice and a decent loupe it's not very difficult to move the DOF or change perspective the way I want to without really contemplating Scheimpflug principles. I force myself to read up on them a few times a year, and every time I get a little closer to understanding. And in the meantime I'm out in the world straightening buildings, and maximizing the DOF by making it run parallel to the ground. For more info on the infamous Theodore Scheimplug and his rule check out this link:
http://www.columbia.edu/~akj19/scheimpflug.html
http://www.trenholm.org/hmmerk/index.html#SRpicR