Brown was the right man at the right time, backing up well to collect four tries.
Hughes showed another dimension to his all-round game by setting up two attacking kick tries, while fullback George Williams took over in the second half with smart kicking tactics giving Ruapehu territory and denying a desperate Kaierau even a bonus point.
The veteran side were not flawless with a lot of dropped ball and messy lineout throws, while seeming to get the better rub of referee Noah Viliamu's whistle in close contact situations, and they could have racked up 50 points had Andrew Evans left the goalkicking to the accurate Craig Clare.
Kaierau fullback Anaru Saurara and second-five Kameli Kuruyabaki had moments where they could break out, but these were far and few between, with their brave but smaller forward pack being pushed around at scrum time and weary from the physical contact around the ruck.
What hurt them was players making half breaks and finding no-one anticipating to back up, along with basic problems like missing kickoffs.
Teenaged first-five Ethan Robinson did his best against the former Highlander Clare, with the team still missing leader Ace Malo while fellow veteran Areta Lama showed glimpses of his old form when he came on in the second half.
"Not perfect, but good for the boys to get up," said Evans.
He complimented Williams' attacking kicks in the second half, and Brown for being on the spot for his tries.
"He'll have to shout a box at training."
Ruapehu could still use a couple more backs coming into the team and Evans said they cannot treat this coming weekend as a foregone conclusion.
"Ratana will have a point to prove. We won't be taking them lightly."
Kaierau coach Denis Edwards had to take a similar mindset - "we just got to go bowl Border now."
While a frustrating match, he was pleased his team, with an average age in the mid-20s for the forwards and under 23 in the backs, did not give up.
"We just made some wrong decisions at the wrong place on the field. We made critical mistakes.
"That's the experience in the [Ruapehu] team that we just haven't got. They've got some very good old heads in there that know how to play."
It started well with Ruapehu making fumbles on the hitups and Kaierau getting the territory for centre Hoani Pahl-Long to put them up with a penalty.
But Hughes spotted the chink in the armour as he chipped ahead and Saurara was in two minds, getting a rough bounce which Hughes gobbled to score.
Saurara redeemed when Ruapehu dropped the ball at Kaierau's line and he kicked into open spaces - getting there as the fastest player on the field and grubbering again - as
Pahl-Long was stopped by a desperate tackle on the line, yet recycled back for halfback Cameron Davies to make it 8-5.
Ruapehu swiftly got back to the line, and although Kaierau's forwards managed to stop one signature drive, an offside penalty led to a 5m scrum and the pack drove again to give No8 Campbell Hart his easiest try this year.
Evans cut through a gap out wide and laid down a grubber kick, which Ruapehu's chasers swarmed on at the corner flag and after a consultation with the linesman, Viliamu awarded Brown his first try and Clare nailed the difficult conversion.
Clare added a penalty for Kaierau being offside again for 22-8, before the hosts replied after a Ruapehu fumble - attacking on both sides and despite not backing up players in gaps on three occasions, they maintained possession and Kuruyabaki was finally able to put winger Stuart Brosnahan across.
That should have given Kaierau a lift with just three minutes until halftime, yet Ruapehu play every available second and working forward off penalties, they attacked with Tutauha putting Williams over untouched for 29-15.
The roll continued after the break with Hart running to the posts, and although the ball was lost, Kaierau just gave it right back with Hughes cross kicking for Brown to dive on the ball at the line.
Kaierau gamely hung in there as the forwards responded with their best interplay of the game to get back down to the tryline for Saurara to sneak through the ruck for 34-20.
But it proved their last shot fired, as Kaierau's spilled ball was spread wide and with a four on one overlap, Ruapehu put Brown into the corner. Williams kicked for territory and then put a seal on the match by setting up winger Mikaine Mareikura, who ran to the line and threw the ball overhead for Brown to make it four tries.
Ruapehu 44 (Troy Brown 4, Jamie Hughes, Campbell Hart, George Williams tries; Craig Clare pen, 3 con) bt Kaierau 20 (Cameron Davies, Stuart Brosnahan, Anaru Saurara tries; Hoani Pahl-Long pen, con). HT: 29-15.