Shifting -- Your Mountain bike likely has a very wide rear cassette. Means you have a wider range of gear ratios to choice from without changing the front ring. I lot of road bikes will have cassettes very tightly spaced.
Example of a SRAM Road 12/26 10 speed cassette: 12, 13, 14, 15, 16, 17, 19, 21, 23, 26
A similar MTB cassette might be 11, 12, 14, 16, 18, 20, 22, 25, 28, 32 or 11, 12, 14, 16, 18, 21, 24, 28, 32, 36
Those hoods and brake levers are not adjustable (if I remember right). To increase braking you can:
Clean the rims and pads, you might be surprised how much this helps.
Adjust the pads so they are closer to the rims when not in use
Change the pads to new ones.
To smooth out the road bumps a bit on the same frame/fork/wheels you can put some wider tires on there and run slightly lower tire pressure. Put some 25mm tires on there if it has 23mm and run them like 90 front and 100 rear. If you are running 23mm at 120psi right now, try 100 front and 110 rear. Depending on your weight you might be able to go a little lower. I've been switching most of the tires we use from 23mm to 25mm. Only time 23mm wide tires now are on race wheels designed for that width tire, otherwise it's 25mm and a bit lower pressure.