If you want to be sure i don't see a problem with taking the valve cover off to confirm the dots on the idler gear and timing gears line up. However if you are going to crank the engine you need to hook up the intake parts first and any other sensors you may have unplugged. So make sure that anything that has a plug is plugged in, otherwise your engine probably wont even think about running and if it does you'll probably get CEL's up the wazoo. I dont know what dash lights youll get if you dont have the accessory belt on: you'll probably get a CEL or idle issues if the power steering pump doesnt have any pressure. Same goes with the alternator not being hooked up.
Honestly if you insist on cranking the engine and it does run, i wouldnt run your water pump dry for more than 30 seconds.
If you are really questioning your judgement id say that taking off your valve cover would answer more questions than turning the engine over, and it will take less time...