The Volvo XC90 isn't meant to be a proper off-roader. I know this because I read it in the owner's manual at the end of a long scrabble up a hill track of brick-sized granite stones, halfway up one of the Mourne Mountains. It looks like a mud-plugger with its ground clearance, knock-absorbing trim and 4WD badge, but you won't find a picture in the brochure of one on anything other than tarmac.I'd already found out it was an excellent road car - I'd covered a thousand miles with three kids to get here - but munching a sandwich on this rain-lashed hillside looking back down the steep track to the stream we'd forded at the bottom, I now felt gently impressed at its climbing abilities too. It didn't have a transfer box, differential locks or any of the other bells and whistles of dirt work, but it did have electronically-controlled four-wheel drive which feeds drive to the wheels getting most grip . . . and this was all most 4x4s ever really needed.This was a mid-level SE version of the prodigious seven-seater with the most recent addition to the engine range, the 2.5T. The five-cylinder turbocharged petrol unit uses 210bhp to haul the two-tonne monster up through the 62mph mark just 9.5 seconds from standstill. If you must have a petrol engine this one makes the most sense of the range. The bigger 272bhp T6 engine can only strip 0.2 seconds off that sprint time, yet it's thirstier and costs over £3000 more.I say it was the SE version, which costs basically £33,735, but it was carrying a lot of extra goodies like a five-speed sequential automatic gearbox (£1250), leather seats and trim (£2260), a pop-up sat-nav unit (£2500), built in phone hard and software (£900), a Mini Disc player on top of the standard-fit 6-CD autochanger sound system (£275), a sunroof (£850), electric-memory seats in the front (£600 upgrade), heated seats (£225) - the list goes on.One extra that thoroughly impressed the kids was the back-seat DVD player with remote headphones (£2175). Across the entire width of the Scotland and half of Ireland I got no peep from either of the two in the back. Thank you Volvo and Doctor Who.I can't say the car is Tardis-like because although it's big inside, it's big outside too. The turning circle is better than you'd expect for such a huge vehicle but the occupants are dwarfed by the massive external dimensions. Inside you get a choice between seven seats or, at the tug of a few tabs and the push of a few squabs, a host of optional spaces down to a flat-bottomed cargo hold with cathedral-like capacity. Even with five seats up, the boot with its useful split-tailgate entry would have swallowed four times the amount of luggage my family needed for this two-week holiday.The XC90 is an excellent journeyman's car. That turbocharged 2.5-litre engine is powerful enough to get you first away from the lights, the gearchange in automatic or sequential mode is all but imperceptible, it's quiet and smooth even at high speeds with engine rumble, road noise and wind rush kept to a minimum, and the suspension is comfortable yet keeps any roll through the corners far from alarming. The seats go from impressively comfy electrically-adjustable ones in the front, through averagely supportive in the middle, to kids-only in the boot.The main problem with the engine is that although it's a fine mile-eater, it washes those miles down with copious amounts of petrol. I managed an average of 23mpg and that included a lot of gentle-footed motorway cruising.So if I were to be given around £34,000 to spend on a big petrol off-roader, would I spend it on the XC90? Well, the competition is tough, but if you want your big 4x4 biased towards the road but with some limited mud-plugging ability, you want to be able to take all your kids and a couple of cousins too, and you want something roomy, easy to drive and very comfortable, the XC90 2.5T is right up there on top of the tree.Personally, I prefer a bit more go in the dirt than the Volvo can deal with, but the only thing to touch it in the price bracket with the same internal flexibility would be a diesel Discovery . . . and that's cheating. Engine 2521cc, 5 cylinders Power 210bhp Fuel/CO2 23.9mpg / 282g/km Acceleration 0-62mph: 9.9 seconds Top speed 130mph Price £33,735 Details correct at publication date