https://incendar.com/
This is enitre Valencia 1 Quest Line for Main Story cut down to 24 minutes., which is 48 or 49 quests. This took me 7.5 hours straight but I cover and highlight any part of the quest chain that ended up taking time to save you lots of time. I think this can be done in 4-5 hours. Here are some recommendations to make this quick and mostly painless from my experience.
1.bring a friend or friends to cut down the kill times and make some quests easier. 4-5 hours is possible!
2. Take some tea/water/silver with you when you head to the desert and Valencia City, you need the high quality wine from the cook npc at one point. You can even just collect sale off marketplace there if you forgot.
3. Talking to NPC at bassiliks and Centaurs you can avoid the mobs if you are low level and gear.
4. At the end of this quest-line you have an option of 4 quests MAKE SURE to check the ring reward on each one before you hand in or you will be stuck with a ring you may not want.
5. Fast mount will definitely make this faster!