I need lower gears 4 hills on my road bike

[Seajay]

I have always struggled climbing hills. Every hill I usually manage to redline. My heart rate is crazy high and my breathing, well it's more akin to gasping.

Why don't I get similar gearing set up put onto my Dolce?

I have this crazy idea that I want to ride the USA southern tier route. But I need a bike that is comfortable for riding hours day after day. I want a more upright sitting position (personal choice) and it's going to be mostly credit card touring.
Any thoughts Ladies?

I would encourage you to look at your climbing a little bit.
Starting off too fast and having out of control breathing is a big problem.
I'm going to guess that you have had some tingling of your nose lips or fingers during these climbs as you have been likely focusing on INHALATION.

Next climb try starting out 10% slower and focus on having purposeful EXHALATIONS. Consider a little backpressure, exhaling against pursed lips. You should see a drop in HR and less hyperventilation. Over time your speed will improve but you can focus on finishing in control first.

What are you using for a pedal and shoe system? If you are using open pedals or toe clips with running shoes, it may be time to consider the huge improvements you can see with a "clipless" pedal and shoe. Use the winter to have a slow easy learning curve.

At first I couldn't understand why someone with climbing issues would switch from a Dolce to an LHT. (Porsche to John Deere) Then I read the rest of the post and it made a bit more sense. But why such a tank of a bike if you already struggle climbing?

If you are at or over 5'5" and planning a credit card tour....which is not crazy and you SHOULD do. .... Perhaps take a look at some of the newer commuter cross bikes.
Something like the $1K Trek CrossRip (5'5-6" = 49cm for Trek) comes with a triple front crankset and weighs 5 lbs (more than 15%) less than the LHT. Upright position and pretty much any tire size you want. It should be able to take a 30T rear cassette with no problem. Likely even the SRAM PG850 11-32T would work fine. So for an additional $30 you would have 50-39-30 up front and an 11-32 in back.