14 year old gravely 252Z starts intermittently

I have a 14 year old gravely 252Z. It has been a great mower for many years. Last year I took it to a gravely dealer and had them tune it up, adjust the levers and hydraulics, new blades, etc. to the tune of $700. It worked great for a couple of months, then it started acting up. You would have to turn the key multiple times to get it to turn over, but it would eventually crank. I had the starter rebuilt a couple of years ago, and this year I took the starter and solenoid in to the same electrical service place and they replaced the solenoid and said the starter was fine.

I put the starter and solenoid back on, but I am having a problem getting it to start. Sometimes it will start, and other times the red light will come on when you turn the key, it makes a clicking noise, but doesn't turn over/crank. Sometimes it will start if you use the power boost on my battery charger. I had my 3 year old battery checked and it had 0 volts, so I bought a new one. I put in the new one, and cleaned the battery connections, but it does the same thing, turn key, red light comes on, hear a click, but it doesn't turn over.

I saw the thread on this site suggesting potential bad fuses, safety switches, or connections. I even got a wiring diagram from a different local gravely dealer. Does anyone have any suggestions on how I should go about trying to correct the problem. I don't have a trailer to haul it on, and I'm hoping I can figure it out without spending another pile of money on it. Of course they will happily come get it for $75 in addition to however much it costs to fix it.

I suspect it's something simple, a bad fuse, a loose connection, a bad ground, etc. Any help or suggestions would be greatly appreciated. I love the gravely, and it's been a wonderful mower. Please help me get it to start correctly, just like old times.

14 year old gravely 252Z starts intermittently