Westfall is mainly 10-12 up to about 20, with some further quests later on, and an instance zone in the middle (Deadmines).
Sentinel Hill
You should arrive in Westfall from Elwynn Forest with two quests: Furlbrow’s Deed, and Report to Gryan Stoutmantle. Deliver his deed to Farmer Furlbrow, who is one of the first people you will meet. Then collect Verna Furlbrow – Westfall Stew and Poor Old Blanchy, Farmer Furlbrow – The Forgotten Heirloom. Then move to the next farm south to deliver the stew request to Salma Saldean, and collect Salma Saldean – Goretusk Liver Pie and Westfall Stew, and Farmer Saldean – The Killing Fields (save for later). Keep looking for sacks of oats that you can safely reach, and report in at Sentinel Hill. Make sure you check the flight path with Thor and register at the inn.
You should also collect: Gryan Stoutmantle – The People’s Militia, Captain Danuvin – Patrolling Westfall, Scout Galiaan – Red Leather Bandanas, and Quartermaster Lewis – A Swift Message.
Save the message for your next scheduled visit to Stormwind City for spell/ability upgrades. Start to work around the farm in NE Westfall collecting oats, and killing young fleshrippers (10-11), goretusks (12-13) and golem hastvesters (9-12). You will probably want to leave the goretusks to later. The recipes also require murlocs, which are on the north coast close to the Furlbrow’s, and are 11-14.
You also need defias trappers and smugglers, which drop the red leather bandanas. There is a camp of them quite close to Sentinel Hill directly to the northwest and due east of the guard tower, another due east of the tower, and further north at the Janglode Mine, and at Furlbrow’s Farm (where his watch is: note that this is guarded by a level 15, Benny Blaanco, and you will only be able to reach the watch at this level if someone else is killing here). While close to the mine, hunt gnolls on the north headlands as well.
By this time you should have gained a couple of levels (on two different characters, with a warlock I was 13, with a paladin 15, and 16 hours on the paladin), and the harvest watchers (14-15) for the Killing Fields are going to be feasible.
The main chain quest here is going to be The People’s Militia, leading into other quests relating to the defias. You will now have Gryan Stoutmantle – The People’s Militia (2), kill pillagers and looters (levels 13-15, in Moonbrook, the Alexston Farmstead, and the Gold Coast Quarry); and also Gryan Stoutmantle – The Defias Brotherhood, which requires travelling to Lakeshire, in Redridge Mountains. I think that I’d move to Redridge at this point, and come back after doing the basic quests in the Lakeshire area, before moving on to the murlocs and harder gnoll quests in Redridge.
The Dagger Hills
Gryan Soutmantle – The People’s Militia. Kill highwaymen, knuckledusters and pathstalkers in the Dagger Hills (15-18); the highwaymen are possibly all 17, and are well spaced out along the Dagger Hills, although there is a camp at each end; the west end is the easier entrance, but in the middle, SE of Moonbrook, there is a narrow ravine leading up.
Grimbooze Thunderbrew – Thunderbrew Lager; in the mountains in the south, used for a Redridge quest (Dry Times). He has his own camp in the middle of the Dagger Hills pass. He wants five hops from the harvesters.
The Westfall Lighthouse
This is in the southwest, just south of where Old Murk-Eye can usually be seen on the beach. The beach close to it and the waters when crossing over are safe; you can scramble down to the beach close to Old Murk-Eye.
Captain Grayson – Keeper of the Flame(oil from the harvesters).
He also gives: Captain Grayson – The Coastal Menance (Old Murk-Eye, level 20) and Captain Grayson – The Coast isn’t Clear (kill murlocs), levels 13-20. Tidehunters and Oracles are south of the quarry, Warriors north of the quarry, and Coastrunners on the very far north shore. First complete the Defias quests.
Remaining quests:
Scout Riell – Red Silk Bandanas (elite, linked with the Defias Brotherhood quests)
drop quest (murlocs) – Captain Sander’s Hidden Treasure 16; drops from murloc tidehunters (18-19) in SW