It’s easy enough to reach Penang by land and sea from Malaysia’s capital Kuala Lumpur, for example, by taking the train to Butterworth and then taking a ferry from there, or by taking a bus across the bridge into Georgetown.
Penang also has its own airport, and you should have no problem hiring a car here – the roads in Malaysia are amongst the safest in Asia, and some of them are spectacularly engineered.
Penang is an easy enough place to get around using local buses, but a hire car can also be useful for heading back into the mainland and then driving into the rainforest to the east.
Should you rent a car in Penang? It’s far from essential, but it might be worth looking into.