you doing
this?
Bear in mind that some passes may not be open.
It's lovely: I did it the summer before last. The Col de L'Iseran still had snow and ice in mid-June. (see pic - my bike)
Go as light weight as you can. The gradients are not extreme, but even 6 per cent gets to you after a while.
And take clothing that caters for all contingencies.
Have fun.