I wouldn't worry too much about snakes and spiders! In all my years of hiking and camping in pretty remote places, I have encountered a grand total of 5 or 6 snakes, most of whom ran away from me pretty promptly
The only person I know who's been bitten by a snake was gardening in Hampshire and got a nip from an adder
As for spiders, I don't know where you live but I had more spiders living in my house when in London than I do now in Melbourne!
Camping is definitely an acquired taste, but really the camping on these kind of rides is just like sleeping in a very small room
If you're not sure about it, can you borrow a tent and sleeping bag from someone and camp out in the garden for a night or two to see if it's really not for you? Ultimately you have flushing toilets, hot showers, people cooking your meals for you, and then it's just a matter of getting used to getting ready in the morning in a smallish space, and if you take the sleep-easy option the tent set-up/pull-down would be removed from the factor completely.
I haven't done any riding in WA, but did the Great Victorian Bike Ride for the first time last year and loved it. The riding can be done at whatever pace you want, and apart from a few wet days, I had some of the best cycling I've ever done on that ride
Still a cyclist, albeit one who never rides any more....