We've been doing about 3 vintage trailer events a year all withing 20 - 450 mi. to them, as with you. So we've been renting TVs since 2013, but are currently looking for a used `08-13 Cayenne S as a TV/3rd car now that we're doing 5 a year & getting close to retirement when we can do more trips. Here are my recco's for the options....
There are some Toyota dealerships which will rent a pick-up or SUV equipped for towing & actually allow towing (typical Hertz, Alamo, etc. will not allow you to tow). We rented Nissan Pathfinders during 2014 from a dual Toyota & Nissan dealership, but they were 45 mins. away. they allowed us to just use our AAA insurance for the rental, but we'd still be liable for loss of use (same as with renting a car).
Most dealerships only have rental cars for customers with their own vehicles in the shop, so you'll have to call around to the dealers listed on the Toyota Rentals website.
Enterprise Truck Rentals (Enterprise Commercial Rentals - not the local car rental ones) rents 1/2 & 3/4 toin crew cab pick-ups for towing duties, but you'll need to either use their daily rental insurance or add them to your policy (not likely), & it is a good idea to open a business account with them for this, & you can write off rentals if the trips are for business (even if family comes along).
In both cases - you can only tow within your own state - at least in CA, but it may be different back there for you - so ask them.
They both also have a certain limited miles per day or week which is included in the price, over which you pay a stiff per mile fee in addition. So figure your round trip needs + incidental miles running around before/during/after, then pick either the number of days or week(s) which break even vs. the per mile charge on the minimum days you need it. Usually about 4-5 days is the break even point to go for a full week & pay the same. The rental staff can help you with that.
Our rentals ranged from $300-500 for 3-4 days, to $700-1000 for a week - depending on which vehicle & miles & whether their insurance was paid.
Been there, done that - & when I ended up buying at the end of the lease, I found that I'd paid 2x what just buying it outright, & the 72 month term loan payments would've been not that much more than the lease payments. Back then IRS rules on leasing vs. buying made the business write-off better on the lease, so it worked out with me on that basis. However, if you're in business & can write it off, then check with your accountant to see what's best for you under current IRS rules.
Note that lease rates are typically higher than interest rates - especially in recent years since they dropped so low. Beware of any added payments at the front end or back end of the lease, because there are several catch 22's in the lease terms.
Plus, you're basically paying for a long term rental of the value lost on the car over the term - or the part not covered by the "residual" value which they expect it to be at the end of the lease term (which is also usually your purchase price to buy out of the lease at the end), but beware that some leases allow them to "recapture" any added depreciation below their "residual value" estimate, as a balloon payment at the end of the lease.
Moreover, the lease only allows a certain max. miles per year & over the total term - over which you pay a per mile fee at the end of the lease (similar to the car rentals with limited mileage), which can be a killer! They can also charge you for any damage to the vehicle at the end. So you need to closely watch your use & mileage of a leased vehicle.
Otherwise, IMHO you're better off buying recent used or new - as you prefer & what works best for you. Do some research on lease vs. buy.
You say you need a pick-up for work anyway, so if it works in your budget, then get pre-qualified for a new &/or used car loan, & use a longer term to bring the payments down closer to leasing if need be. New you can generally finance 100% of the cost with license, taxes & other fees - whhile used can vary by age for 70-90% Loan to value (LTV).
Then keep in mind that with a new car, you lose 20-25+% of that vehicle the second that you drive it off of the dealer lot! That can be a big hit & can have most folks underwater on their loan for a year or two, until payments bring the principal down to what the then current used car value is at. If you plan to keep the car/truck for 7+ years, then that may be okay to have that initial loss of value, in return for the new car warranty, etc. - but there are "other ways to skin that cat" as they say!
A late model used car/truck which has been well maintained, carefully used - or even pampered, with relatively low miles, & possibly a used car/CPO warranty can be a far better bargain.
There are both dealer demos & executive cars which come on the market in about a year or when they reach 7-10,000 miles which must be sold as used - as well as 1-3 year old early trade-ins with low miles by buyers who want to change cars or just want a new one every year - which can be great bargains.
And when purchased from the same make dealer & checked out & pass their inspection, they can have a factory CPO Warranty (Certified Pre-Owned) which can be equal or better than a new warranty - but you need to check out each one's, since they do vary between makes.
For example, a new Porsche warranty is 48 months/50,000 miles, but their maximum CPO if done before the new warranty expires is 72 months (6 years0 & 100,000 miles. So it's feasible to find a 10=4 year old Porsche at 10-40,000 miles with a longer & more miles factory warranty - than new! Other makes are different, but this is an example with which I'm familiar due to our current used Cayenne S TV search.
You may have to search more for that perfect used TV or other used vehicle, than a new one - but then you may not be able to find the perfoect color & options new at a dealer or even special ordered.
Also, in 2015> many of the makers are down-sizing engines to meet the increasing CAFE fleet fuel mpg requirements, so many are replacing the V8s which many of us prefer for towing, with smaller turbo-V6's which will have to rev higher & more often under load.
So IMHO, buying a nice used one is the best option once your rental costs start to equal the "cost & feeding" & insurance of owning your own TV - unless a lease works for your business write-offs, or unless you want a special order & plan to keep it a long time.
You can also rent while you patiently look for that perfect - or nearly so - used TV.