female travelling alone in may

Train journey takes lot of time from Trivandrum to northern india(say,Delhi).You will get tired unless you like trains journies very much. If you are keen to take train, then make reservation in 3 tier Airconditioned class for comfort and safetravel. Note that you need to make advance reservation much in advance.May is a rush season due to holidays for school children. Suggest you to check some budget airlines also.

Incidentally, rainy season will start in Kerala(Trivandrum) sometime around 10th May and it purs heavily..So watch out.
Rest of India will have summer season. Summer temperatures would be 43degC+...so suggest you to go to mountains in the north.
Have a nice trip.

if you are open to trek in the indian side of the himalyas in may end pls b in touch

Ladies carriage - that's what I would recommend for a long journey by train if you are alone.
You will be safe in any train class, but the extensive attention can get really tiring.

Have travelled all around India by train. It is a great way to travel. Buses are OK but train to be preferred. Recommend you get yourself a copy of "Trains at a Glance"as soon as you can - buy from bookstalls on station platform - and then you will be able to work out where you can go from where, and when.

Make your first journey in first class. Let's you in gently. When you've acclimatised - trade down to second class - much cheaper; perfectly safe.

Good advice by ninataka here.. I would follow this if i was you, Trains at a glance is a must have thing it will save you loads of time once you understand it ........