This is a very simple "guide", that contains the Baldur's Gate 1 in-game "world map" with all the travel times, written on it. Basically it is a graph that has locations as vertices and travel routes as the weighted edges.

Notes:

• In some cases, one travel route has two different weights. This is because the game treats those routes differently, based on the direction you travel. Presumably, you are moving up/down hills. If this is the case, use the weight written closer to the departure point.
  
• The map overlay is highly misleading. Sometimes places located next to each other have a day of travel between them; sometimes it is the other way around.
  
• The map overlay is taken from BG1 Enhanced Edition (BGEE) ver. 2.6.6, which I believe will be the last official version. Notice that the overlay can be different for earlier BGEE versions or for the original BG1 / ToSC. I swear, every time I play this title, Durlag's Tower and the Archaeological Site are in different places. I would guess these are cosmetic changes though, and the edges / weights would be the same, but I didn't check that.
  
• There are points of "fast travel", related to quests. For example, you will be teleported to Nashkel after you arrest Captain Brage, or you can be taken inside the Bandit Camp as reinforcements. Some of those cases are instantaneous (Captain Brage), while others advance time (Bandit Camp). I didn't put those on the map to avoid spoilers and to not overwhelm the map.

All of the travel times are checked manually and personally, so you don't have to.

Have great Sword Coast adventures!