Since it's not all the time, I think the cheapest way would be to drive really slowly and find the best angle to hit the incline.
A larger diameter set of rims and tires would set you back $1000 or more and give you a tiny bit more clearance.
Location: Coquitlam BC, Canada (Greater Vancouver area)
Hybrids: 2010 Toyota Prius Touring (& former HCHII owner)
Re: How to increase ground clearance
I was thinking about methods for increasing ground clearance for our Honda Civic Hybrid, as a consequence of several severe snow storms we had last winter. Our clearance is not that great, and worse than the regular Civic's due to aerodynamic panels on the underside.
One thing I found out was that in Brazil the Civic is marketted with 1~2 inch more clearance. So, it is doable. I also found the vast majority of research is into methods for lowering the car, LOL. Bottom line: it would be expensive, may void warranty, put off potential buyers down-the-road, etc, etc.
In our neighbourhood, up the hill, a lot of people with steep driveways have taken to kerfing out a notch at the crest.
The easiest way would be to put rubber inserts inside the springs, it looks like thick, hollow, rubber disc with grove, cut on the side. You lift the car to uncompress the spring and you put it between spring coils as far high or low as it would go. Now, with the rubber insert, portion of the spring will not compress as much, keeping the car higher. It is usually used for older cars with worn out springs, but should work as well on TCH. Another way would be to put adjustable air shocks, where you can lift the car by pumping up pressure inside the shock. Either way, make sure to check handling of the car, as it will make the suspension stiffer and could cause some side effects (for example less stable in straight line driving). It could also change some wheel alignment. I would also look into fixing the grade of driveway or maybe just find out if driving up at an angle, instead of straight up, did the trick.
The reason for fitting such smallish tyres, are of course the need to keep a low centre of gravity for mainly roadgoing vehicles - but the wheels fitted to RRs and Discoveries are still bigger than the opposition. And as a dedicated offroader manufacturer Land Rover has a joker up its sleeve: the huge amount of axle articulation make easy work of even big boulder crawling with standard fitment sizes. Nonetheless - improved clearance will improve the vehicles capabilities even more, and let the vehicle fly through areas beyond reach with standard sized wheels. Bigger wheels also translates into better traction.
There's always practical and economical considerations in every modification, so it's worth summing up everything connected before commencing any work - and checking every issue in detail with fellow Land Roverists having done same thing before as you intend to do. The economic side of it also calls for addressing the issues in this article whenever you're into changing tyres or springs or shockers - you won't like to invest in new springs this year and buying bigger wheels calling for taller springs next year... But you can fit taller springs this year and wait until next year when tyres wear out; but there's only some instances when you can fit bigger wheels this year and only next year fit taller springs.
Part of the reason why TCH has such low ground clearance is fuel economy. The lower ground clearance allows improved aerodynamics, which is one of the major factors in fuel economy. The roughness of the underside of the car, the air pressure in that area, and a whole bunch of other factors, all contribute to the friction that the vehicle must overcome.
I suspect the ideal would be to have lowered ground clearance for smooth paved roads, and increased ground clearance for rough roads, or driveway entrances.
The Camry and Camry Hybrid share the same chassis with a few minor differences.
* The overall height of the Camry Hybrid is 57.5 inches, which is almost half an inch shorter than the other trims of the Toyota Camry.
* The ground clearance of the Camry varies by model as well:
o The CE and LE (4-Cylinder) trims have a clearance of 5.5 inches from the ground.
o The V6 LE, SE (4-Cylinder), and V6 XLE trims have a clearance of 5.3 inches from the ground.
o The V6 SE trim has a clearance of 5.1 inches from the ground.
o The Camry Hybrid has a clearance of 5.9 inches from the ground.
So it seems the TCH already has "increased" clearance, by almost a half an inch.