general.txt

Here are some general principles I used for D&D 3.5 to GURPS DF/DFRPG conversion.
Your opinions may differ.

1 gp of treasure in the adventure equates to $1.  You can either just say that
in your game $1 = 1 gp if you want the piles-o'-gold-everywhere D&D feel, or
convert the gold coins to silver or copper if you prefer to keep the DFRPG money
rules.  (I started off with 1 gp -> $4, and that was way too much treasure.)

1st-level D&D 3.5 characters are around 125 points.  Each additional D&D level
is about 25 points.  So characters at the bottom of the dungeon (15th level)
should be around 375 points.  (I gave out too many points; my 5 PCs were around
500 points when we stopped between levels 12 and 13, which I think was too
much power for this dungeon.  As a result some of my monster conversions on
the deeper levels are pretty overpowered, to try to match the PCs.  If you have
more reasonable PCs then you probably need to tone down the opponents some.)

I did XP per session, but that makes it harder to keep the PCs at the right
power level, if they finish a dungeon level in a different number of sessions
than you expected.  (If you think it should take 5 sessions, and they take 12
sessions, that's a lot of points for going too slowly.)  I would recommend
instead doing a very small number of XP per session, with significant amounts
of points for "finishing" a level, and maybe a few bonus points (not too many
unless you feel your PCs need the help!) for accomplishments like finding
secret sublevels.

A DC 15 check is an unmodified GURPS skill roll.  Each 5 points of DC is a -2
to skill.

DC   skill modifier
10    +2
15     0
20    -2
25    -4
30    -6
35    -8
40   -10

And then interpolate any in-between values: a DC of 22 is a -3, for example.

I tended to convert Masterwork weapons as Fine, +1 weapons as Fine and
Balanced, +2 as Fine and Balanced and +1 Accuracy and +1 Puissance, etc.
Assume that people who enchant weapons aren't dumb, and will go for the
less expensive mundane bonuses before the more expensive magical ones.
For unbalanced weapons like axes, I often threw on Dwarven, for foes who
are supposed to be a challenge, since not being able to parry freely is bad.
Penetrating Weapon is very good, and perhaps appropriate for some bosses,
especially if your PCs wear a lot of armor.

Alignments are a problem.  Typically, items that only worked for Evil, like the
Crown of Narborg, I would make incompatible with all the PCs.  For intelligent
items that are picky about who uses them (Scalemar, Aquil'iya, Charithmysis,
Spear of Elweiss), I tried to figure out which PCs met their standards, and had
them shun the others.  (Charithmysis shunned them all, because none was a real
bard.)

A lot of the monster conversions were found on the GUPRS Wiki and various
blogs.  If you just web search "GURPS monstername" you often find a good
starting point, though I had to amp a lot of them up to provide any challenge.
D&D 3.5 monsters are often huge bags of hit points, which doesn't translate
that well to GURPS, so I would usually reduce the HP a lot, but give more
active defenses.

HT has a lot of influence on enemy staying power.  Much less than 12 and they
go down really fast to spells (in particular, Concussion).  Much more than 13
and they tend to stay up to -5 * HP, which can get tedious, unless your PCs
are good at brain shots to give big penalties to stun checks.  Unnatural is
a good disadvantage choice for a lot of monsters, as it lets them have a lot
of base HP, but reliably die at -HP instead of -5 * HP.

Check out the blog at https://dfwhiterock.blogspot.com for more general tips
about running this adventure.