It will really help you to know some Malay. Some people speak English, but do not expect everyone to be able to. The local Terengganu accent is quite thick, but most people also speak "standard" Malay.
Most visitors to the Perhentians bypass the bulk of Terengganu and instead transit via Kota Bharu, in the neighboring state of Kelantan, which offers better connections by air and train and is only one hour away. However, Kuala Terengganu and other locations along the main north-south highway are accessible via long-distance bus from Kuala Lumpur, Penang and various other cities.
Kuala Terengganu's own Sultan Mahmud Airport (TGG) does field a number of flights daily from capital Kuala Lumpur. It's a two-hour drive from here to Kuala Besut, the usual jumping-off point for the Perhentian Islands.
There is a substantial network of paved roads in the state.
There are many intrastate bus routes. In addition, if you stand by the side of the main coastal highway in a village, you can hail intercity buses if you want to go to Kuala Terengganu or other major cities in the state. The intercity buses will usually stop if you hail clearly enough for the driver to see you.
Many tourists come to Terengganu to go to islands like the Perhentians to swim and scuba dive, but the coast itself is beautiful and pleasant and dotted with peaceful villages (kampung in Malay), and Tasik Kenyir, a reservoir lake in Ulu (upriver) Terengganu, provides breathtaking panoramas.
Terengganu is known for local fabrics like kain songket and kain batik. The Pasir Payang Market (Pasar Besar Kedai Payang) in Kuala Terengganu is the best place to pick up some.
Terengganu's most famous culinary product is the keropok lekor, a thick hot dog-like sausage entirely unlike the thin deep-fried crackers called keropok elsewhere in Malaysia. Keropok lekor is made from fish paste and sago palm flour and should always be accompanied by a reddish-brown dipping sauce of tamarind, chili, sugar and vinegar.
Much good inexpensive food is to be found in coffee houses (kedai kopi) along roadsides in villages, and of course in cities. And do not miss the chance to buy some of Terengganu's delicious fresh fruits in any of the pasar (bazaars) in the cities and larger towns.
Nobody seems to be quite sure if it's legal or not, but turtle eggs are widely sold in Terengganu. They're a threatened species, so think twice before you indulge.
Alcohol is generally looked down upon throughout Malay-dominated Terengganu and is served only in Chinese (non-Halal) restaurants. It is possible to buy Malaysian and imported beer by the can at large grocery stores.
Non-alcoholic drinks are widely available, including fresh juices, coconut water (air kelapa), corn drink (air jagung) and the array of packaged drinks sold elsewhere in Malaysia. The widest variety of branded products is available in Kuala Terengganu, but there are drink stalls on the side of any major road.
Terengganu, with its nickname as Darul Iman (Abode of Faith in Allah), is known as a conservative, Islamic state. You will have a better experience if you respect local mores when you are outside of resort areas where people are used to foreigners dressed in bikinis. It is not necessary or expected for non-Muslim women to wear a headscarf (though it would certainly meet with approval), but both men and women should wear clothing that covers all or at least most of their legs (no short shorts), and women should wear blouses or dresses which cover their torso. Long sleeves are preferable for women, and outfits which show the shoulders or midriff should be avoided. The watchword is modesty. Tourists dressed in shorts and skimpy tops are really out of place in this state.
Culturally, Terengganu has a lot in common with the neighboring state of Kelantan, but the cultural and historical differences between the two states make Kelantan interesting and well worth including in your trip to Terengganu. A bus ride from Kuala Terengganu to Kota Bharu lasts only about three hours.