Ques. Which is the reliable way to get wifi internet connection in the roaming for my Samsung Chromebook?
Ans. There are multiple ways to use an internet connection while roaming.
3G/4G wifi hotspot through your smartphone- this is simply using the the 3G or 4G connection in your phone to provide internet to your laptop or other wifi enabled devices.
Using a 3G wifi dongle from Airtel/Vodafone/idea that can be plugged into a wall socket or a USB power source.
If you are roaming outside the cities then getting a 3G signal in villages or remote areas is quite difficult. You will only get 2G connection and the internet at 2G speeds is absolutely slow for browsing on a laptop.
So if you are roaming in remote areas remember to take a CDMA wifi dongle connection as even the lowest speed in a CDMA internet connection is good enough to browse websites unlike 2G GSM connections which are too slow.
Tata photon and MTS are the leading CDMA internet providers.
One more piece of advice: As you have a chromebook avoid buying dongles which do not have Wi-Fi on them as plain old USB only internet dongles may not be compatible with your chromebook. Wifi ones will work out of the box.