Digibud,
The Vado SL has too low torque (and too low assistance) to consider it for serious climbing if you are not extremely fit. The Vado 5.0 would be a good choice with some restrictions.
The Specialized 1.3 (Brose S) motor found in Vado 5.0 is a monster. It will give you up to 550 W peak power and 90 Nm torque, making it one of the strongest mid-drive e-bike motors in the class (I don't talk about Chinese cr*p). I assume your favourite ride does not consist of only climbs. Rest assured you might cover your 35 mi/3500 elevation gain route with Vado 5.0. When you are about to ride up the steepest climb, you just switch the assistance to Turbo and the Vado would take you up the hill with the flying colours, so strong the motor is. On easier climbs, the Sport mode might do, and you'd be riding downhill either by not pedalling or with the assistance Off to conserve the battery charge. (There are options in the Mission Control app to tune the assistance the way your route would be completed on a single battery charge as well).
As I have said, there are some restrictions.
Vado 5.0 has been designed for speed, not for climbing. Therefore, it sports a 48T chainring and 11-42T cassette. The simplest mod would be replacing the cassette with the Shimano Deore XT CS-M8000, which is 11-46T, 11 speed one. That would change your lowest gearing from 1.14 to 1.04. You could also try the Sunrace MX 80 11-50t 11-speed cassette, giving you the granny gear ratio of 0.96.
@Sierratim, thoughts?
There is worse situation with the chainring. There is a large thread about chainring replacement in the Specialized forum here. It is not so easy to find a proper replacement chainring, although it is doable. Ironically, Vado 4.0 (that would be not the best for your specific needs) comes with a 40T chainring.
Tyres! The 5.0 comes now with the Trigger Sport 47-622 tyres. If you consider riding dirt roads, the stock tyres might not do their job well. Vado 5.0 accepts up to 2" tyres but only slick ones. You could try 47-622 tyres designed for (potentially) high speed and with a good offroad grip such as Continental Top Contact II -- in case you find the stock tyres not performing well on your rides.
If the 5.0 is available in your area, go for it. It is a fantastic e-bike. The problem is there is limited availability of e-bikes nowadays and it is hard to even suggest options other than the Vado 5.0 today.
I think other users will also contribute.