New to me 2003 30' Terry Dakota, tires shot

Hi All!  Just purchased my first travel trailer and there is so much to learn.  I've been reading blogs, forums and watching videos and still have a long way to go.

I'm picking up the trailer this Saturday and everything passes my inspection except for tires.  They are badly dry rotted, C load range ST tires, 205/75R14.  The trailer GVWR is 7200#.  Curb wt is a guess as the seller repaired some water damaged floor, figure 6000#.  I've got about 10 gal. in the black water tanks and the others are dry.  The air pressure is at 45 psi.  I know it should be 50, but considering the condition of the tires, I'm trying not to stress them too much.

I found some Carlisle's Radial Trail HD (D rated) sold and shipped by Walmart to home.  No pickup at store.  I've never had tires installed at Walmart, so that is my first question... what to expect?  Do I drop off the trailer unhitched?  Leave it hitched and let them drive my diesel truck?  Or wait for 4 hours? in my truck?  Waiting room?  Is getting tires mounted that I bring in a hassle?  Do I need the receipt showing I purchased from Walmart?  Please share your experience and suggestions!

Also, I'm going to go straight to Walmart when I pick up the trailer.  It's about 3 miles away at 45 mph.  I was wondering if it's possible or even practical to get 15" rims so I can buy E rated tires?  I'd like to be able to load the trailer to GVWR and not have to worry about under rated tires.  The Carlisle's will arrive Friday if I order today, so quick responses are much appreciated!

Happy travels!

check etrailer.com.. You can purchase rims at a reasonable price from them... Also purchase the metal valve stems to install on the rims..  Check for tire clearance to be sure that the 15 wheels and tires will have enough room if you install them...  I had the same tires on my trailer and was also concerned about the weight problem.. I went one size up to a 215 75R14  Goodyear Endurance Tire that is D  rated and has a much heavier capacity rating than the 205 C rated... Saved the additional dollars by not buying all new rims... Put the tires on and headed west... Put 2000 miles each way in a 12 da;y period... So far tires have been great with each additional trip we made... Tires are also made in the good old USA... Not Chinese... Some Carlise are made here, but the majority are made in china...
Good luck with your new unit...

If possible I would take the wheels off and just drop them off to have new tires mounted. Going with a heavier wheel and tire is not a bad idea if they will fit. A blow out on a trailer tire at speed will destroy the side of the trailer. (I speak from experience).  Also while the wheels are off is a good time to pull the drums and check the brakes. Tires and brakes are the only safety margin you have between the road and your family, so don't overlook the important stuff. 

You don't need "E" rated tires.  The ST205/75R14 will carry 1760 lbs each at 50 psi (LR "C"), which ought to be adequate for any 7200 lb GVWR trailer with two axles. The axles carry a combined total of 6500 lbs, so about 1625 per tire.  The "C" range is sufficient to give some extra margin and the D load range is probably over 2000 lb/tire and thus more than enough.  However, If you want still more load capacity, change to 225/75R14. That size will be about 10% greater in load carrying.

You don't need to have the tires installed at Walmart unless you want to. You are going to pay for mount & balance wherever you go, so its your choice.  Most Walmarts can use a portable jack to change tires in the parking area adjacent to the auto shop, but check with the store about that capability and where to park the trailer. Some stores have easily accessible parking at the shop, while others are better suited for drive-through.  Just leave the trailer, or wait for it (usually a couple hours).

Walmarts shops often have low skills and high employee turnover, so don't expect a lot of expertise, especially on something they don't do often. I would check tire pressure and lug nut torque before I left the premises.

All good advice, gents.  Well taken.

I had a heck of a time getting a human on the phone at most of the Walmarts near me.  I did find one with a VERY helpful tech in the Auto Care Center.  He said they didn't have a suitable jack for my trailer, but gave me a direct line to another store that might.  It was too far away, so I called a local RV dealer to see what they had and what they would charge.  They only service vehicles they sell but referred me to a Tire Store they use.  He was extremely helpful and even suggested I go with the Carlisle Trail HD, which is the one I wanted (based on comments I read on this forum).  Plus, he said I should check bearings and brakes while we're at it, so he was one step ahead of me on every point.  Suffice it to say, I have an appointment for Saturday.  He's a little more expensive than Walmart, but cheaper isn't always better.  I don't  mind paying for peace of mind.

I thought about taking the wheels off, but I think I'm going to risk it driving the 7 miles.  I'll have a chase vehicle behind me in constant voice contact.  I'll keep it under 35 and stop after a few miles to check tire temperature.  Worse case, I have to call a tow truck.  Thanks again for all the tips.  I'm staying with the 14" rims, D-rated.

Sounds like you are right where you need to be!

Good choice. With new tires, and brakes and bearings inspected, you will be ready to travel.