Sg - Ipoh not that far la...6 hour plus can reach. Assuming you start sg very early morning, you'll reach Ipoh around early lunch. From Ipoh up to Tanah rata only 45 min - 1 hour nia. The last major rest area before simpang pulai is Tapah. so you can freshen up, makan etc.
If you come from NSH, exit at the Simpang Pulai toll. Turn right and when you reach first traffic light (i think), turn right and the road will lead you past some marble quarries and then gradually up to Kampung Raja and then down to Brinchang (equatorial hotel). from there the road leads you down to Tanah rata & then ringlet. So if you drive from Sg, i think take this new road is better...faster, not so much turns hence not so tired. Coming back to sg, you can take the old road down to ringlet which you'll then lead you out to Tapah and just follow the signs to NSH.
I agree that at Brinchang is the highest and the Boh tea plantation at Sungai Palas (in that area) is very nice!. I know cos I took my wedding photos there ...or you can drive to another boh tea plantation lower down in somewhere past tanah rata area. I think it's near Ye Olde Smokehouse.
A word of advice, if you go weekends or school holidays, be prepared to wait and have traffic jams up in that area...my friend's car got stuck in that traffic jam and it was all the way uphill and his engine overheated!...
Tanah Rata is THE main town area with lots of restaurants and shops and cars and stuff....Brinchang rather quiet and ringlet has LOTS of flies....dunno why.
but it's a nice place to take a few days of R&R..