Save the game after you've played it for a while and then quit to
DOS.  Use  a  Hex  editor  to  change  the following bytes in the file
GAMESAVE.*:

Offset          Meaning
16              Difficulty level (1-4)
29              Rank (0-9)
30 & 31         Money (00 10 for $4096)
34 & 35         Days left (01 00 for 10 days)
18              Riding (0-9)
20              Mechanic (0-9)
22              Brawling (0-9)
24              Wealth (0-9)
26              Charisma (0-9)