From what you've described, it sounds like the starter turns the engine over, but does not fire. Just cranks and cranks.
I would verify there is actually fuel flow near the engine to rule out any clogged fuel filters, or pump issues. Crack the fuel line near the engine and see if you have flow there, don't need to take it apart completely, just crack it loose to allow fuel to come out to verify the pump is sending fuel, there's enough pressure that a crack in the line will spray fuel pretty good - be careful.
On plugs, are they original or been replaced lately? They can cause non-starts where it just cranks, but does not fire if they are too worn out.
Lastly, if you have an ODB (or ODBII) port, see if you can borrow a code reader. A true non-start due to most malfunctions should show a code even if the engine won't start. That could help you track down the problem if you've verified fuel and spark.
The crank in any gear, sounds like a failure of the transmission position interlock relay (Park or Neutral should be the only gears). Not messed with those on new cars, old cars it was generally in the start circuit, so bad relay generally meant no crank.
Good luck.