You have 2x10 joists 16"oc with a 14' span and a 3/4" t&g subfloor? You can lay that floor any darn way you want to. If you are ultra fearful of running it parallel to joist, blocking every 24" would be plenty. And the blocking would not need to be full joist thickness. A 2x6 would do fine, it would just need to be placed directly against the subfloor.

Solid joists as opposed to engineered joists are often inconsistent in their levelness due to crowning. It is possible you may end up with an undulating floor because of this even if you have strengthen the subfloor between with blocks. Once the subfloor has been exposed check with a straight edge to determine whether it will be flat enough for you. Bear in mind if it is a prefinished floor you are installing each surface will reflect as if it were a small mirror and accentuate the rolling nature of the subfloor.

I too cannot see the savings of remove+replace. A sand/refinish averages $5/sf. It is minimally disruptive (ie. it does NOT involve demolition) and it will cure in 10 days (assuming you are using a high-end water based finish). Now an engineered hardwood is SUPPOSED to be more expensive than solid. Yah. I said it. Engineered (same cut, width, thickness, installation method) should be more expensive than solid. Hmmmmmm. My spidy senses are tingling. Now on to the cost of hardwood upstairs. Carpet removal/disposal = $1.50 - $2/sf (depends on where you live). Repair and prepare the wooden subfloors (usually 'bad' underneath carpet...carpet hides the WORST subfloors) $2-$4/sf. Yep. Just ASSUME you will be spending $3/sf for the subfloor prep upstairs. Now for the cost of solid hardwood (regular 3" width) = $5/sf. Installation + finishing = $3-$4/sf. Right. A regular solid hardwood (nothing special) with install = $8 - $10/sf. Now compare that to a 'sand and refinish' of $5/sf. Wow. It is CHEAPER to do the sand and refinish. Hmmmm. Now imagine the COST of demolition for the HARDWOOD....yep. You can add MORE to that cost. And again the subfloors have to be looked at. More costs. Now imagine the cost of a MORE EXPENSIVE engineered hardwood....$8 - $12/sf for material only. Installation is extra ($3-$4/sf for factory finished hardwood). I tell ya. The $5/sf sand/refinish is looking REALLY GOOD right now. Ignore the width of the planks. They are classic and are probably appropriate for the age of the home. It is your money and your home. If you believe an engineered hardwood is CHEAPER than $5/sf sand and refinish (including install and subfloor preparation) then you are welcome to find out the reality of the situation. We are going to tell you the 'cheap' wide plank engineered hardwood is not going to give you the 'life expectancy' that a 'regular' 3" wide solid hardwood ($5/sf material). It just won't.

Do you think it would look better to have the whole upstairs hardwood running in the same direction, as opposed to switching how the hardwood runs in the master bedroom? My main concern is entering the master bedroom, the floors won't run left to right they will run front to back I.e. perpendicular to how the bed is situated but also perpendicular to how the light (south light) hits the room.