I am a T2, also I am a or was s keen fair weather cyclist, it's not affected me in any significant way, but as many of us are affected differently by this condition.
I think what's most important to cycling distances is to eat ,drink often, as you would anyway to keep energy levels up,this is more important than normally would be the case, depends if you are affected by what us cyclist term as The 'Bonk' ,'Knock' , 'packet', in other words low Blood sugars , I only once suffered from that during my serious cycling days, but being Diabectic is something to be wary off, not that T2's suffer from this very much, more a problem for T1.
Metformin has affected me to some degree, I don't tackle long rides as I used to, some days I do have classic Metfarting belly, I feel under par for cycling, I have cut back on Carbs, a lot , but will eat some if I know I am going to be excercising or use a lot of energy,so I think carb loading isn't such an issue if you are going to be very active.
Of course ,as always seek medical advice, but in the end you know yourself better than others, it's a new journey for you, you need to explore your boundaries.