The Atlantic crossing, even with the circumnavigation of Africa, is shorter than the Pacific crossing.
There are other reasons why the Atlantic crossing is more likely:
1. Circumnavigating Africa offers voyagers multiple stops for supplies, including food and water, that you don't get crossing the Pacific.
2. Everyone agrees the Mulekites crossed the Atlantic. Even John Sorenson agreed with that. (BTW, Sorenson documented other evidence of transoceanic voyages here.)
3. The winds and ocean currents work for an Atlantic crossing, but make a Pacific crossing implausible.
4. There is historical evidence to support ancient crossings of the Atlantic. Columbus crossed the Atlantic, using the same currents and winds as the ancient explorers did.
5. Around 600 B.C., Phoenician mariners circumnavigated Africa.
6. In 2008-2010, a ship reconstructed using 600 B.C. materials and technology circumnavigated Africa. The currents and winds sent them across the Atlantic to within a few hundred miles of Florida before they managed to turn the ship around back to Africa. See this page.
There are a lot of web pages that show Lehi crossing the Pacific Ocean to land in Mesoamerica. I looked into the rationale for what seems such an implausible theory. The most common explanation is that Lehi would have to cross the Pacific to land on the west coast of Mesoamerica to make the limited geography Mesoamerican theory work. This is especially important to explain why, in Sorenson terms, west is south (i.e., they landed on the south-facing coast, which the Nephites thereafter considered "west"). (For those new to this issue, the Mesoamerican proponents claim the Nephites didn't use the same cardinal directions we do today, except when they were in the Old World. Once they arrived in the New World, the Nephites based their directions from the first landing on the south coast of Mesoamerica, which they equated to the west coast of the Mediterranean, so that when the text mentions "northward" and "southward," it really means "westward" and "eastward.")
I know how ridiculous that sounds, but that's what you'll find if you read what the Mesoamerican proponents write.
Another rationale may be Orson Pratt's claim that Lehi landed in Chile, which was likely based on Frederick G. Williams' note of unknown origin. The Mesoamerican proponents reject that specific landing spot, of course, but they like the Pacific crossing part of it. I don't see how one can rationally accept part of Orson Pratt's theory without accepting all of it, but that's what they do.
Yet another rationale is 1 Nephi 17:1, which says "And it came to pass that we did again take our journey in the wilderness; and we did travel nearly eastward from that time forth. And we did travel and wade through much affliction in the wilderness; and our women did bear children in the wilderness." It seems apparent from the context that Nephi is describing their journey in the wilderness, not on the ocean. In fact, he never mentions directions once he gets on the ship. Here's what he says in 1 Nephi 18.
8. And it came to pass after we had all gone down into the ship, and had taken with us our provisions and things which had been commanded us, we did put forth into the sea and were driven forth before the wind towards the promised land.
21 And it came to pass after they had loosed me, behold, I took the compass, and it did work whither I desired it. And it came to pass that I prayed unto the Lord; and after I had prayed the winds did cease, and the storm did cease, and there was a great calm.
22 And it came to pass that I, Nephi, did guide the ship, that we sailed again towards the promised land.
23 And it came to pass that after we had sailed for the space of many days we did arrive at the promised land; and we went forth upon the land, and did pitch our tents; and we did call it the promised land.
From this, I conclude one should look at the prevailing winds and sea currents--which lead to a route around Africa and across the Atlantic.
Conclusion. Backing into a Pacific crossing to support a Mesoamerican setting makes no sense to me. Unless one wants to accept the Williams/Pratt theory of a landing in Chile, which has its own problems, I don't see any reasonable explanation for assuming a Pacific crossing. Now that we have documented evidence of the real-world feasibility of 600 B.C. technology taking a route from the Arabian peninsula around Africa and across the Atlantic to North America, and we all agree that the Mulekites crossed the Atlantic, what basis is there for assuming an implausible Pacific crossing?
There's a more detailed discussion of this issue here.