There are many places to level in the mud. The following is a rough guide for new/old players.
Refer to this site for speedwalks to all areas http://morit.p4o.net/speedwalk.htm
This searchable database has near complete list of all items & equipment http://
Places to level:
Mud school (Recall, up, s) - Go for the snail, rabbit, lizard, boar. Take note of the bear and beast, they are Agro mobs. Remember to set to wimpy (type Help Wimpy) so that you can autoflee if your hp drops too low.
For good newbie equipments, refer to this in HOTL3 site http://hotl3.com/help/newbie7.html
Mob factory (recall, 2s, 3w, 3s, 1e) - Go for the worker and fido first. Engage the Cityhead after you have learnt and practiced your first skill (see Help Class, Help Books, Help Learn).
The Circus (recall, 2s, 3w, 9s) - Go for boy/girl, then mother/father etc outside the circus. To enter the circus, buy a ticket at the ticket booth (10 gold) and use it to unlock the door. Beware of the agro animals inside. A newbie item here worth getting is the Strongman's bracer. Kill Ivan the Strongman outside the circus for a key, then go to his tent inside the circus and use the key to unlock the locked chest.
Canterbury (recall, 2s, 15e, open e, 12e, open e, 5e, 1s) - Go for the boy/girl, followed by peasant, then nobleman/noblewoman. After that Jester/Toymaster/Pie-Man etc that are in the East and West Playground.
Cloudy Mountain (recall, 3s, 3e, s, up. look for gold coins and type exits / hunt for 'man') - Go for the guard and soldier, then Anarchy if you are good aligned or Virtue if you are evil aligned. After that the Bodyguard if you are capable.
Underdark (recall, 2s, 6e, 4s, 2e, s, 2e, d, w, s, d, open d, 2d) - This area is for the good aligned. Go for the Underling then Dretch. The recall points are outside jaded hall (underling) or forgotten alley (outside dretches).
Temple of the White Lotus ((need boat or waterbreath) recall, 2s11w2s1w1s1e2s13w6n1u2w to temple guard, give gold to guard and go south) - This area for evil aligned. Go for Assistant then Buddha.
An alternate location for those of evil alignment is Canterbury. The pardoner/summoner series.