Are you planning on selling the LC? You have a '14 so you're already eating pretty massive depreciation just on the newness of your particular truck. Any way you slice it your opportunity cost is higher, but hey, your money, your cars.
It's not as if you're doing something wrong, just pointing out that your justification's flawed. I'm in a similar boat - right now we have 3 cars and no daily commute other than taking kids to school, so all this stuff is just a luxury, including the 80 series I bought to park at DIA and avoid buying my -V snow tires. But it's not saving me any money.
What's your insurance on the RX? Guessing even just that incremental cost is about the difference in your LC vs RX MPGs....
1000 miles commuting a month @ 13 mpg = ~77 gallons of gas @ $2.50 = $192.50
1000 miles commuting a month @ what, 22 mpg? = $113.75
So $78 difference in gas saved from the LC. ~6.5 years to break even just on a cheap $6k purchase price not factoring in maintenance and calling gas savings & insurance a wash.
My vote is for driving awesome cars whenever possible, which is how I racked up 35k miles on my -V in less than 2 years. Re: hail, that's what insurance is for. If you have a 50 mile commute you may as well try to enjoy it. Bill Shatner said it well:
[youtube]