I'd agree with Duke that your usage is not too bad given the circumstances. The puff of blue on startup is indictive of valve stem seals in my experience. They are a realatively easy job so long as you have access to an air compressor. The parts are CHEAP (although you will want to replace the valve cover gaskets as well).
I did mine last year when rolling a new timing chain and replacing the upper chain guides so it was really almost an afterthought. (Given your mileage, the chain guides are something you should probably consider if you haven't had them replaced already.) The new seals cut blue smoke to zero and oil consumption is low enough that I no longer add oil between oil changes (every 4K).
'87 560SEL 267K (177K on motor) Blue/Blue
'98 Buick LeSebre 60K (wife's car)
'56 Imperial Sedan 124K
'67 Dodge Monaco 130K (Sold)
'87 Chrysler 5th Ave 245K and going strong (sold)
'73 Plymouth Satillite 175K (sold)
'96 Chrysler LHS 80K (totaled)