this thread is a little dead so I might as well try and revive it (I couldn't do yours cerasium) here's 4 balloons i've set throughout the first campaign. they are of varying difficulty to find and pop. some pictures maybe be rotated to make it harder. good luck!
Bad vibes under the coaster: https://www.freeriderhd.com/t/993175-molta-world-pt-ii +1 if you can get the missing slot (closest to the ramp)!
This balloon is made of double-thickness latex, requires two ghosts to pop: https://www.freeriderhd.com/t/53080-yellow-mountain
Rage balloon. 30 mins on this section, really wanted a flag there. https://www.freeriderhd.com/t/676621-bhr-ghosting-collab-2k15