Centaurus, if it was me, I wouldn't be too capable of logical thinking in the situation. I'd have both feet jammed on the brakes with full back elevator trying to slow the aircraft as fast as possible.
In the event that an obstruction is still approaching too rapidly, I'd still have both feet firmly planted on the brakes with full back stick and trying to steer with the nosewheel. There'll still be some steering capability dependent on forward speed. I would imagine if the speed were still high enough, a bootful of rudder will have the aircraft turn sideways soon enough and possibly bury a wing if that is the intention, although I've never had the opportunity to try this.
That being said, if I couldn't steer the fuselage clear of an obstruction, I think I'd still rather take the crunch head-on rather than a posssible side-on. My seat belts were designed for a head-on restraint and there is a nice engine in front with mounts, etc that can act as a battering ram and obstruction for any extraneous materials (like goalposts, building walls and materials and trees). Passengers can bury their heads below the dash for protection. It should certainly offer better protection than a door, a side window and a wing. I can't see any benefit in turning the aircraft onto its side.
A river would be one of my last choices in an emergency with fixed gear. I'm not keen on a sudden flip at high speed, dazed and confused, upside down under water and trying to get a seat belt off and out the door and swimming in the right direction in darkness for the surface. And I'd have the benefit of some familiarity with the aircraft that my passengers wouldn't have. Not to mention the possible post-accident infections and infestations that might result from a dip in the Yarra.
You never mentioned about landing on a street or road. That would be my choice over a football field any day. If you land with the traffic, you'll touch down at the same speed or a little faster than the cars and trucks, so the drivers should have the opportunity to avoid you. Just keep a good lookout for crossing power lines. It seems to work in the US on a semi-regular basis.
"No use to try for fancy riding now.
And, Clancy, you must wheel them, try and wheel them to the right.
Ride boldly, lad, and never fear the spills,"
Just my thoughts...