I am running Return to Temple of Elemental Evil. The players found out about the location of Rastor, but I can't find any information about it. Looking at the map I estimate it's about 250 miles and the travel would take them a little less than a month, because of difficult terrain. What the exactly is the distance from Hommlet to Rastor?
Here is a screenshot from the world's most accurate currently available map of the Viscounty of Verbobonc.
Using the scale on my graphics software as a ruler, the distance as the crow flies from Rastor to Hommlet is about 150 miles. While this might be a somewhat challenging flight to accomplish via psionics or magic, it's still possible. Easier would be a magic carpet, airship, or similar device. This is also well within the range of teleportation effects.
However, unless one of the above is available, horseback is going to be the rule. The shortest route travels through the area marked as the Free Assembly of the Kron Hills.
This route starts from Hommlet and passes through the Thorp of Sheernobb. It then crosses into the so-called Free Assembly of the Kron Hills (established in CY 587 after the death of the old Viscout Wilfrick). However, since you are running the Return to the Temple of Elemental Evil, this should put you time-wise in the late CY 570s: otherwise known as the "Second Uprising of the Horde of Elemental Evil"; thus the Free Assembly has yet to have rebelled against Verbobonc and be established.
Next the route passes through the fortified castle of Kron, through a few minor unnamed gnomish villages, and then into Tulvar, which will someday become the capitol of the Free Assemblies. From Tulvar a long stretch through the gnomish village of Osnabrölt, and then into the human village of Loren's Ford and on through the small towns of Validia and Tristane and finally arriving in the village of Rastor.
Using the map scale as a ruler, I come up with the following approximations:
- Rastor to Tristane is about 40 miles, on a tertiary road (which are poorly maintained, and do not usually have any bridges over fords, and not patrolled, so rough going).
- Tristane to Validia is about 30 miles, across hills and valley, on a secondary road (reasonably decently maintained, occasionally patrolled).
- Validia to Loren's Ford is about 15 miles, through hilly and mountainous terrain on a secondary road.
- Loren's Ford to Osnabrölt is about 10 miles, through hilly and mountainous terrain on a secondary road.
- Osnabrölt to the southern spur is about 10 miles, and then on to Tulvar is about 18 miles or so for a total of 28 miles through mostly valley terrain on a secondary road.
- Tulvar through the three unnamed gnomish villages and on to Kron via the Greenway Valley is just over 25 miles, call it around 28 miles total along a secondary road.
- Kron to the Thorp of Sheernobb is barely 5 miles on a secondary road, but it goes through a mountain pass, so we'll just round up to 5.
- Sheernobb to the eastern spur of the Kron Hills is about 7 miles, and from there to Hommlet is about 5 miles, so we'll call that 12 miles total. This is along fertile plains, so should be fairly easy going along the secondary road.
My estimations using the map legend on this map as a ruler result in a total of 168 miles (approximately). Given the twists and turns of the trails in question (not to mention the ups and downs of the Kron Hills) one could easily round this up to effectively 200-250-ish miles with no problem.
Add in some encounters along the way - especially along that ill-patrolled stretch of road between Rastor and Tristane - and you can set them back a month (or more) of travel time, easy.