Gravity

The formula, if I've done it correctly, is
r = 6.378 * sqrt (m/g)
r = radius in MU
6.378 = radius of Earth in MU (assumes 1 MU is 1000km)
m = mass of primary in Earth masses
g = gravity quantity you want (in gees)

Note also that Traveller book 2 (my edition, anyway) has some
errors in the planetary stats, eg Jupiter is listed as 1318
Earth masses where I believe it's actually 318; Saturn is 714
when IIRC it's more like 95.  I suspect they forget about
density.