How long would it take to travel through a wormhole?
There's a recent popularization of wormhole physics that nicely lists the properties of the four wormhole examples that Morris and Thorne considered in Appendix A of their 1988 paper ("Wormholes in Spacetime and their use for interstellar travel: A tool for teaching general relativity"). These properties include traversal times. Here's a summary
Infinite-Exotic-Region Wormhole (exotic matter distributed throughout space) ~ 1 hour
Large-Exotic-Region Wormhole (exotic matter confined to large finite radius) $\geq$ 7 days
Medium-Exotic-Region Wormhole (exotic matter loosely restricted to throat) ~ 200 days
Small-Exotic-Region Wormhole (exotic matter closely restricted to throat and must have negative mass) $\geq$ 0.7 seconds
Morris and Thorne referred to the last example as "absurdly benign". It is not dissimilar to the thin-shell wormholes considered by Visser. In fact, some of Visser's thin-shell wormholes are a special case of the Morris-Thorne Type 4 "absurdly benign" class!
These times are completely independent of the distances between the mouths of each wormhole in normal space.
Sources:
"The Physics of Stargates: Parallel Universes, Time Travel, and the Enigma of Wormhole Physics" by Enrico Rodrigo (2010), Chapter 5.
Visser, M. (1989). Traversable wormholes from surgically modified Schwarzschild spacetimes. Nuclear Physics B, 328(1), 203-212.
Visser, M. (1989). Traversable wormholes: Some simple examples. Physical Review D, 39(10), 3182.
Morris, M. S., & Thorne, K. S. (1988). Wormholes in spacetime and their use for interstellar travel: A tool for teaching general relativity. American Journal of Physics, 56(5), 395-412.
Standard reference for wormholes:
Visser’s book
Excellent Wikipedia page:
Wormholes
From Wikipedia page:
“Wormholes which could actually be crossed, known as traversable wormholes, would only be possible if exotic matter with negative energy density could be used to stabilize them. (Many physicists such as Stephen Hawking,[1] Kip Thorne,[2] and others[3][4][5] believe that the Casimir effect is evidence that negative energy densities are possible in nature.)”
The paper which started the whole “traversable wormhole research in the 80’s-90’s” is written in a very pedagogical style:
Morris, Michael S. and Thorne, Kip S. (1988). "Wormholes in spacetime and their use for interstellar travel: A tool for teaching general relativity". American Journal of Physics 56 (5): 395–412.
Given the above background info, the answer to your question is: A traversable wormhole is basically a “hollow handle” which you can use to reach two different parts of the universe. It is like a tunnel, BUT there is no definite relation between the “length” of this tunnel (or the time you/light rays need to travel thru it) and the “distance” between its mouths (entry/exit points) as measured in the space-time outside the wormhole.
Put it in another way: we can find a solution to the Einstein’s eqs with a wormhole connecting two areas in space-time a few light years apart or many 1000’s light years apart. Basically: given the desired G tensor, we can find the appropriate T tensor (that is the appropriate energy-matter distribution) so that the wormhole can be comfortably traversed by a human (or a light ray) in a short time (hours, for ex.).