It's not hard to check the valves. It's actually fun to see what goes on under the valve cover. Probably just need a shop manual, feeler gauge, and wrench to turn the engine. With the engine cold, turn it to TDC on the compression stroke (with the spark plugs out, the compression will push on your palm over No. 1 sparkplug hole), check the valves that the manual tells you to check. Write down the readings in your manual. Then turn the engine the way the manual says and check the next ones. When you finish, see if any are out of specs. Hopefully, none will be. Otherwise you have to take the cams out. If you check them you will probably need to replace the valve cover gasket.