From Lahore, the best way to reach Hunza by public transport is to catch any Daewoo bus service to Rawalpindi and from there catch NATCO Bus (Pirwadhai) which goes directly to Aliabad, Hunza (via KKH - Abbottabad, Mansehra, Besham, Dasu, Chilas, Gilgit, Aliabad). However, be prepared for long journey on NATCO as it takes 20+ hours. From Aliabad, you can reach Karimabad (main tourist spot) by local suzuki van for 50 Rs which hardly takes 20 mins.
By making Karimabad your main point, some of the attractions include Eagles Nest (Duikar), Altit & Baltit forts, Attabad Lake, Hopar Glacier, Diran Guest House (Minapin) and if u have more time then go to Naltar valley which is more nearer to Gilgit.