Bath is a city in England.
Option 1: London Road roundabout
Walk down to the end of London Road until you get to the large roundabout. You want the first exit for the A46 which goes to the M4 (GB). There are two lanes and so a vehicle can stop for you in one of these lanes (there is no layby at this junction). Most drivers will be driving to the M4 (J 18) from this roundabout - the motorway onramps at J 18 (East and West) have plenty of space for vehicles to pull over. Using a sign here could take you a long distance in either direction, to London, Wales or even North up the M5 (GB) User:Xael Impala often hitches up to Worcester using this route).
Option 2: Weston/RUH
Simon recently [July 2017] had great success getting a quick lift from just past the RUH Hospital to the M4 (GB) junction, driving via Lansdown (past the racecourse). Drivers will often use this route to avoid going on the often congested London Road. It is also much used by drivers coming from the west side of Bath.
South-East towards Trowbridge, Warminster, Salisbury
Walk to the start of Warminster Road, which is the A36 going out of Bath (past Sydney Gardens). On the left of this uphill road there is a place for cars to pull in. Wait times can vary but rides will often be going long distances down the A36. Also a good spot if hitching to Stonehenge.
West towards Bristol
Go The Golden Fleece pub on Lower Bristol Road (near Lidl). Opposite this pub is a red letter box which is a good place to hitch from. There is space for a driver to pull over in the Bathwick Tyre shop. A sign here for Bristol would be helpful.
South-West towards Glastonbury, Devon, Cornwall
As with hitching to Bristol go to the red letter box opposite the Golden Fleece pub. Nearly every driver will be driving to the roundabout on Bristol Road (A 36) where the Globe Pub is. The Globe roundabout is at the end of the dual carriage way and most drivers will know what you mean if you ask to be dropped at the Globe roundabout. There is a bus stop just before the roundabout which is the best place to be dropped off.
From the Globe roundabout walk to the Wells Road (A 39) exit. The best place to hitch hike from is the entrance to Bath Spa University. From this spot you can hitch to the M5 (GB) (avoiding Bristol) and to Glastonbury. Note however that this will likely take a few rides as most people are driving locally. User:Xael Impala has always had swell rides hitching out this way.
Coming from London / the west, there is a junction that heads to Bath with a layby just past the roundabout. Head there. You should get a ride pretty snappy.
Places to avoid
Accommodation and Sleep
Bath has spectacular countryside and it should be quite easy to camp out once walking out of the city in any direction (half an hour from the centre, more or less).
Other useful info
There is a radical underground dumpster diving scene in Bath. For more info: