i lately had my problem on my worlds that i cant trade anywhere but specific spots (mountaintops or single patches of area within a large one that is otherwhise blocked) even on large maps .. even when embarking or planning to next to big towns ..
for a time i use a slightly higher settings of monsters (+ max volcanos and rivers + eroding stuff much more for nice cliffs and flats).. due to being anxious to see something else than the standard ettin or minotaur that die to a first hit of my dabbling soldiers
could there be that beast caves and or megabeast locations block traderoutes no matter what area they go through?
as evidence my settings ...
[WORLD_GEN]
[TITLE:MEDIUM REGION]
[DIM:129:129]
[EMBARK_POINTS:1274]
[END_YEAR:1050]
[BEAST_END_YEAR:200:80]
[REVEAL_ALL_HISTORY:1]
[CULL_HISTORICAL_FIGURES:0]
[ELEVATION:1:400:401:401]
[RAINFALL:0:100:200:200]
[TEMPERATURE:45:160:200:200]
[DRAINAGE:0:100:200:200]
[VOLCANISM:0:100:200:200]
[SAVAGERY:0:100:200:200]
[ELEVATION_FREQUENCY:1:1:1:1:1:1]
[RAIN_FREQUENCY:1:1:1:1:1:1]
[DRAINAGE_FREQUENCY:1:1:1:1:1:1]
[TEMPERATURE_FREQUENCY:1:1:1:1:1:1]
[SAVAGERY_FREQUENCY:1:1:1:1:1:1]
[VOLCANISM_FREQUENCY:1:1:1:1:1:1]
[MEGABEAST_CAP:18]
[SEMIMEGABEAST_CAP:37]
[TITAN_NUMBER:15]
[TITAN_ATTACK_TRIGGER:80:0:100000]
[DEMON_NUMBER:28]
[NIGHT_CREATURE_NUMBER:28]
[GOOD_SQ_COUNTS:25:251:503]
[EVIL_SQ_COUNTS:25:251:503]
[PEAK_NUMBER_MIN:12]
[PARTIAL_OCEAN_EDGE_MIN:1]
[COMPLETE_OCEAN_EDGE_MIN:0]
[VOLCANO_MIN:200]
[REGION_COUNTS:SWAMP:260:1:1]
[REGION_COUNTS:DESERT:260:1:1]
[REGION_COUNTS:FOREST:1040:3:3]
[REGION_COUNTS:MOUNTAINS:2080:2:2]
[REGION_COUNTS:OCEAN:2080:1:1]
[REGION_COUNTS:GLACIER:0:0:0]
[REGION_COUNTS:TUNDRA:0:0:0]
[REGION_COUNTS:GRASSLAND:2080:3:3]
[REGION_COUNTS:HILLS:2080:3:3]
[EROSION_CYCLE_COUNT:1000]
[RIVER_MINS:400:400]
[PERIODICALLY_ERODE_EXTREMES:0]
[OROGRAPHIC_PRECIPITATION:1]
[SUBREGION_MAX:2750]
[CAVERN_LAYER_COUNT:3]
[CAVERN_LAYER_OPENNESS_MIN:0]
[CAVERN_LAYER_OPENNESS_MAX:100]
[CAVERN_LAYER_PASSAGE_DENSITY_MIN:0]
[CAVERN_LAYER_PASSAGE_DENSITY_MAX:100]
[CAVERN_LAYER_WATER_MIN:0]
[CAVERN_LAYER_WATER_MAX:100]
[HAVE_BOTTOM_LAYER_1:1]
[HAVE_BOTTOM_LAYER_2:1]
[LEVELS_ABOVE_GROUND:15]
[LEVELS_ABOVE_LAYER_1:5]
[LEVELS_ABOVE_LAYER_2:1]
[LEVELS_ABOVE_LAYER_3:1]
[LEVELS_ABOVE_LAYER_4:1]
[LEVELS_ABOVE_LAYER_5:2]
[LEVELS_AT_BOTTOM:1]
[CAVE_MIN_SIZE:5]
[CAVE_MAX_SIZE:25]
[MOUNTAIN_CAVE_MIN:45]
[NON_MOUNTAIN_CAVE_MIN:65]
[ALL_CAVES_VISIBLE:1]
[SHOW_EMBARK_TUNNEL:2]
[TOTAL_CIV_NUMBER:40]
[TOTAL_CIV_POPULATION:15000]
[SITE_CAP:1040]
[PLAYABLE_CIVILIZATION_REQUIRED:1]
[ELEVATION_RANGES:2080:4160:2080]
[RAIN_RANGES:2080:4160:2080]
[DRAINAGE_RANGES:2080:4160:2080]
[SAVAGERY_RANGES:2080:4160:2080]
[VOLCANISM_RANGES:2080:4160:2080]
could i be on the right track? had this problem since .16 now