iv done glasgow cumbernauld a few times and id say do the first part (paisley-glasgow )by bike to start off with ,,and do the second bit by train ,,that way you can cool down a bit on the train and not arrive at your work a sweaty knackered mess ,,and do the reverse coming home (train from c,nauld into glasgow ,,bike it from there )and after a while when u get fitter,used to it,, do the whole thing ,,theres a direct train from queen st to cnauld ,,there is not a problem (i dont think )taking ur bike on the train ,maybe diff down south ..but up here should b ok ..get a bike with 700 wheels (much btr than 26"for commuting )the route itself is quite straightforward at both parts ,,straight along prw into town ,,and when ur upto it straight up from queen st through royston and right out takes you to stepps/cnauld,,since they built that new mway its much better for cycling on the road out by mollinsburn and stuff,,theres a couple of hills but nothing major(no granny ring stuff) ,,quite a nice cycle all in
tenn outdoors and decathlon is good for gear(decathlon do a good road bike as well ,,,thisd b ideal),,,id say a road bike proper will make it a bit easier (its all tarmac i think (well the route im talking about is )),,,just enjoy the cycle and dont try for a pb straight away