Walks/camping in the North Island?

Hello Everyone My grownup up kids and I have a Heaphy trip booked for early March. However, it is looking increasingly likely that it will be a no go, with increasing Covid numbers and risk that we might not be able to easily get home to Wellington and Cambridge again, if everything went pear shaped. The huts also may also be a bit risky, bring crammed together at night. I am not so worried about catching Covid from a personal perspective, but my son's kids are both under 5 and therefore unvaccinated. We are all double vaxed and boosted. So we are starting to think about a plan B - a walk for 4-5 days (excluding getting there and back) and camping rather than using the huts. And to avoid using public transport, it needs to be in the North Island. We are reasonably experienced trampers, with good (but not expert) backcountry skills. We did half of the Rakiura NW circuit a couple of years ago. Got round fine but found it tough going in places with extremely muddy conditions under foot. The around Ruapehu/Egmont tracks would be good but I am not sure how much camping is available. Does anyone know if, under good weather conditions in early March, camping on these tracks would be practical? We have good 4 season tents available (and flys). Thanks very much for any advise you can give. Alan