With only 5 days you could consider Murchison with the Kibale Forest (Chimp tracking) or solely the SW of Uganda.
A Red Chilli trip to Murchison would still be a mad dash if going to Kibale also. You could jump off the trip in Masindi on your return to Kampala to source transport to Hoima and onto Fort Portal. This would be a very long and uncomfortable day especially by public means.
Alternatively in your 5 day window you could do an amazing guided waking safari through the Bwindi Impenetrable Forest to Kisoro at a fraction of the cost with Nkuringo Walking Safaris www.nkuringowalkingsafaris.com. Day 1. Bus to Buhoma. Day 2. Guided walk from Buhoma to Nkuringo. Day 3. Walk to Kisoro with 12km dugout canoe trip down Lake Mutanda. Day 4. Trek one of the Virunga Volcanoes in Mgahinga Gorilla National Park or go Golden Monkey trekking. Day 5. Bus back to Kampala.
Anticipated costs per person and could work out even cheaper
Bus to Kampala - Buhoma Ushs25,000-
Accommodation Buhoma Ushs25,000-
2 Day walking safari for 2 persons USD64- including food and accommodation in Nkuringo.
National Park fees Bwindi USD25-
Ranger/Escort fee privided by national Parks USD10-
2 nights accommodation Kisoro USD20- or less
Private hire transport to Mgahinga National park Ushs30,000-
Virunga Volcano climb USD40- which includes park entrance fee or
Golden Monkey trekking USD45- this also includes the park entrance fee
Bus Kisoro - Kampala Ushs30,000-
Meals and drinks in Buhoma, and Kisoro Ushs50,000-
Good luck