What I would do is pick only the important buildings/locations you wanted and put them geographically where you want them, fill the space around them with the less important but filler style buildings. Join them with the more well known of street names.
Remember some of us dont have a clue what San Francisco should be like, Im from Brisbane Australia.
You could look at maps from the original gold box games, they gave a resonable representation (??) of cities and towns people may have visited in pen and papper games. Compare the game map with the pen and paper map and you will often notice certain "important" buildings in the same areas on both.
Obviously you are not going to be able to make an exact representation, but as long as you get the right feel I dont think anyone will mind.
I love the idea of using two maps with a river between them, I will use that one day for sure. but not just one bridge, several bridges at diferent points along the river would be great too.
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The Cauldron -
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