How can I check whether a fork is bent In the case of a crash hard enough to buckle a strong front wheel, how should the fork alignment be checked. The bike is a steel tourer and pretty tough.
Not having fancy tools, I would check for a bend in the direction of travel by measuring the wheelbase of the bike and comparing it to the original specs.  This would work for me, because I've never changed the forks on any bike I've owned, but it may not work for you.

Similarly, not having fancy tools, I would check for lateral bending by putting the bike on a stand, using a plumb line to make sure the down tube is vertical, and then using the line from the centre of the stem to check that it is centred between the front dropouts.