Following listed items are how much of each can be put into a covered wagon

Medievia -11 ale, 8 tar, 85 salt, 35 sugar, 42 raisins
Trilanisti - 56 flowers, 47 arrows, 56 bows, 42 art, 170 parchment
Trellor - 140 perfume, 11 wine, 56 oils, 56 incense, 85 ink
New Ashton - 10 silver, 20 jewels, 21 silicate, 34 nails, 6 copper
Tear/Karlsinia- 28 books, 20 cloth, 68 spices, 11 beer, 42 dates
Rangers Cabin - 11 sap, 68 furs, 1 timber, 34 rations, 37 ivory
Derah - 11 artifacts, 85 candles, 68 herbs, 28 nuts, 34 hemp
Wizards Grove - 34 nightshade, 26 mandrake, 68 spidersilk, 37 slime, 85 phosphorus
Mahn Tor - 3 weapons, 1 chains, 4 pelts, 3 armor, 2 meade
Tar Valon - 28 silks, 68 crystal, 11 rum, 42 figs, 11 molasses
Gdangus - 34 bananas, 42 seed, 48 beans, 43 rice, 56 tobacco
New Genesia - 24 tools, 11 adamantite, 21 coal, 48 opium, 7 iron
Sea's End - 68 opals, 56 ambergris, 56 shells, 28 nets, 42 kelp
Riverton - 42 brandy, 28 metals, 42 honey, 56 grapes, 43 fertilizer
Ruellia/Hidden - 85 emeralds, 280 willowbark, 42 cloaks, 42 rope, 85 waybread
Lyryanoth - 85 venom, 49 hides, 34 eggs, 113 glowworms, 113 mushrooms
Mystara/Cutter - 85 pearls, 17 teak, 14 carpet, 42 maps, 42 fish Elwyn 280 aloe, 170 quills, 112 balm
Urville - nothing, buys cargo only

Trading to and from NaeraMae requires a mule.
Trading to Urville requires a packhorse.