Chris,
You were asking the same questions 3 years ago.
In that time, you should have had plenty of time to go up and explore the river and to find your own spots. I know it is a big commitment in time, I only live 2 hours away from where I fish, and yet I can still arrive there at sun up and have 8-10 hours to explore. You can cover and discover a lot of river in that time. As people have already mentioned, there really are no honey holes or good spots. The whole river is good. Fish move around or may already have been spooked. Where you catch fish one day you wont a few days later. So treat the Bulls them like Steel, cover a lot of water, keep moving (do one cast then step down as you retrieve after completing a swing) and you will find them. Going out exploring and finding them is your commitment/responsibility however we can provide you with tips on how best to catch them if they are there, as follows:
It's a big river, so covering as much water as possible as quickly as possible will give you the best opportunity to hook up. The absolute best way to do this is by swinging a spoon, followed by swinging a fly. Early on in the season, i.e. the past 2 months, egg patterns and drifting beads are the most effective techniques, but you cannot cover water as quickly or effectively as a spoon. As the eggs have now almost disappeared the fish will be hungry for something else and that will be fry, small fish and sculpins, so big sculpin patterns and spoons will become increasingly the weapon of choice.
Flows in the Squamish tend to be big and you need your presentation down near the bottom, almost touching the bottom. I exclusively fish 3/5 or 2/3 spoons depending on the speed of the water. I normally cast approximately 11 oclock across the run, hold back on the line slightly until I feel that first tap as it hits a rock then raise the rod tip more to keep it up and swinging across the bottom. Only wind in line if the flow is not strong enough to keep your spoon from constantly hitting the bottom and snagging. If this is the case snap on a lighter spoon. Retrieve once the spoon is at ~6 oclock.
Make sure to cover lots of different types of water, all types until you figure out where they like to lay. I used to think that bulls were lazy fish and preferred deep pools, because that's where I used to catch them on the Skagit. However, that is not always the case on the Squamish. While I still catch them in the deeper slower pools, I tend to catch more in fairly fast flowing tail outs, straight runs, outside fast water seems and in water with depths between 3-5' depending on clarity. If the water is slightly coloured, you will find them in shallower water. When I say fairly fast flowing, I mean enough that I need a 2/3 onz spoon to get near the bottom. Something like a 1/8 would not work at most of the locations I fish.
The best time to fish is when the water level is between 2-3 m as measured at the Brackendale monitoring station. You can fish outside those windows, but it becomes more challenging. Above 3 m and you need to fish more of the side channels which will now be deep enough to hold fish which are staying out of the high flows. Below 2 m and the water is typically very clear and fish will be hiding in the deeper water or water with a bit of a riffle to provide them with cover. You need to go with 6lbs fluoro in these conditions and smaller spoons and smaller more natural coloured flies.
The best time to fish is on the drop, particularly if the water is slightly coloured. Swing big articulated sculpins in the 3-4 inch length range in white, white/grey, white/black or combinations with olive work very well. Also the previously mentioned spoons in brass, silver/gold or mixed with chartreuse.
Open up google maps and look at where the road gets reasonable close to the river. You can work out the rough distances from the first bridge using google earth. Once you get to a likely look spot, head west and find the river. The more you hike the more likely you are to catch fish. Alternatively drive until you see others parked up and explore.
I recall you mentioned you had a F150 4x4 therefore you should have no problem exploring a little further north of the Ashlue bridge. There is some snow up there at the moment, but not a lot. It is remote area, without cell coverage, so be sensible in the gear you take the choices you make and let someone know where you are going and let them know when you are out.
GL