You will want to beat feet tomorrow to get across Rosario, even though the stronger wind won’t come until,the afternoon it might not come as late as you expect. Sun still sets early and the warmest part of the day before cooling takes over means the wind build may be earlier than you hope. I’d plan for a solid 3 foot on your crossing to Thatcher. Just make a straight shot and go. If it’s already building, you can sneak up north past Eagle harbor and then turn west across the top end and through, but if you really get out by three it might be quicker to head straight to Thatcher. Once you are in it, keep going.
Once across, I’d certainly plan for Friday harbor. Sounds like Friday is going to be lively and sitting in an anchorage tending and bouncing is no fun. If for some reason you need to bail somewhere Thursday after making it through Thatcher your best options are Hunter Bay or Blind Bay, both good holding with South protection. For Hunter, go to the head of the bay and anchor just to the right of the beach in front of the rock face. For Blind Bay, watch the entrance, then alllllll the way up to the head of the bay, left of the floating dock and again all the way up until you get to about ten feet of water. Wind will come over the low of the island, but you won’t get any bounce and holding is trustworthy.
I’d consider Rosario for Sat or Sun and take a short ride to town.
If you don’t think you want to play wave runner Thurs or get a late start, just go to laconner for Fri. Try to hit within an hour of slack to doc, or just make sure the pointy end is into the current as you land, never land stern to current as the current does not play around when running. You could even move just inside of Deception of Fri with enough protection and tie up to docks at Cornet Bay. You won’t want to go through Deception until the wind dies as Southern Rosario has no protection and worse current overhangs in the wrong conditions. But...quick shot to San Juan’s when favorable. Deer Harbor this time of year is deserted, I’d rather just go to Reid and tie to park docks, but make sure your doors are shut after dark to not pick up extra non paying passengers.
Assume you already are aware, you won’t want to cross Rosario in 4-5’s, it’s no fun at all. Three won’t be fun, but you can just shoulder in and take it for the slow hour it will take.
Most important good news is that winds are stable from s to sw. That usually means enough stability to actually believe most predictions. Note one veer to West. If the wind forecast looks good at 5-15, but the direction starts to change to something other than s or sw, start to pay attention. Forecasts should usually be out by 9am, 11am, 3pm +- hourish. If for some reason they are not out, start paying attention again, another indication the forecast difficulty is going up and more unstable conditions. Late forecast and wind shift, start heading closer to home. North wind, go home.