I would do 0-60 in as fast as I could muster when I lived in Allentown at our old apt.
I lived maybe 3-5 mins from the interstate, depending on the sitting I did at the lights.
The highway I would take to work you had to stop at the on ramp as it was designed this way. The Forester has analog auto-temp control. As in no digital readout just a knob to adjust the desired temp. Well a function of this is it will not blast heat until coolant has reached a certain temp.
From the manual
NOTE:
With the fan speed control dial in the AUTO position
and the air flow control dial in the “ ”,
“ ”, or “ ” position, the fan does not operate
during engine warmup until the engine coolant
temperature exceeds approx. 122°F (50°C).
So as the engine would warm I'd start to here turn very slow but it would not run full force until I merged onto the highway. This tells me that I was certainly below or right at 122F coolant temp. I did this for a year with regular 5w30 in the engine and it never seemed to bother the car. I would have to go almost WOT on the cold engine in first gear since traffic was moving along at no less than 60MPH.
Now granted this isn't 90 secs after start although it could be if I got the lights timed perfect point is the car didn't care, I wasn't going to sit & eat gas for 5 mins for no benefit. The car is a tool, used like a tool, sometimes they break if you don't maintain them and sometimes they do even despite that.
Use a synthetic oil and worry little, your car & your stomach will thank you.
As to the suggestion to go slower on the highway as if that is some benefit to the engine. Speed limits are not suggestion, they are cold hard law. If you don't intend to go the speed limit at a minimum then please stay off the highway. More accidents occur from going slower on the highway than speeding. If the speed issue is of concern than do as suggested and take the road to the next exit instead. Speed limits were designed for safety but above all else to control traffic & congestion. Going slower shows no real world benefit to anyone unless you like inciting "road rage".