Hiho!
Local server option is quite good for single-player experience.
But the problem with the map with too much water sounds real. I suppose devs could do something in this direction, like giving an option to reduce water amount upon world generation, if a player wish to play without too much swimming
For now, if you got world with too much water around Bree - you could re-generate you server to have new variant (it's random every time you setup a server first time).
Also having water is not the end... you could try to learn swimming skill (you need just a bit of skillpoints in it).. there are plenty of options, in the guide
https://www.tomenet.eu/guide.php?chapter=4.15 :
The 'Swimming' skill is the easiest choice to reduce tick frequency, and it
does so to zero ie perfect swimming, when maxed. at 0.700 you will become able
to swim very fast, which can be compared to 'running' through the water in
terms of speed. However, this costs precious skill points, so it's not a very
popular way of getting good at crossing water.
Mimics and especially druids can use an aquatic form or a form that can swim
easily, and they will be able to cross water in the same way, without ever
drowning. Another way is to use a form that grants wraithform or simply a form
that grants levitation, which is a rather common ability.
Rangers learn how to swim at great skill at level 25, Martial Arts users will
be able to swim easily at a Martial Arts skill of 30.000.
Ents never drown since they're made of wood, while Draconians will actually
gain intrinsic levitation at level 30.
Characters training the magic 'Water' or 'Nature' school will acquire
water-passing at 40.000, while 'Air' school grants levitation at 50.000.
Other characters can rely on items that grant levitation, swimming (rare), or
wraithform (by spell or item) to become able to cross water easily. Levitation
is definitely the most popular choice, since you can 'fly' over water quickly.
Wraithform is as good as levitation, but hard to acquire.
In short: Obtaining levitation is probably the most popular way for crossing
larger areas of water.