There are plans to develop tourism in the Virunga National Park, in the East of the DRC. One of the planners says that the Congolese tourism sector could equal that of Kenya. Certainly, the region and lodging looks glorious, and the price of the accommodation is reasonable for high quality international tourism. The climate is also suitable for visiting all year.
Evidently, the critical issue for many tourists will be security. The UK government advises against all travel to Eastern DRC. The DRC faces competition from the Volcanoes National Park in Rwanda, which is praised to the skies by tourists, and is far safer.
I think Virunga certainly could be a viable proposition, but the regional or park authorities would have to provide more security. It is financially possible. If a tourist is spending $5,000 on a three week trip, then dozens of security staff could be hired over the period, and the holiday would still generate a healthy profit for the company running the project, and tax for the government. The area of the visit would be necessarily fairly circumscribed, perhaps a hundred square kilometre area near the Rwandan border. The security would have to be established before the tourists came, of course, so risky investment would be required by investors or the government. The administrators on the Rwandan side may be a good source of advice and expertise.