Travel Trailer size question

I'm a real newbie ( just recently purchased my F 250 with a 6.7 Diesel; in the process of installing an aux tank in the bed, after which I will start in earnest looking for a TT.

So here is the issue. My wife and I have done quite a bit of looking at new TT's and 5ers to get some of idea of what we do and do not like, can and cannot afford. Although the balls are still up in the air between TT's and 5ers, I'm leaning heavily towards a TT. Size wise, we found while looking that we felt 28-30 feet seemed to be the most comfortable for us. I have been looking at used units and feel that I am finding that many used units on line tend to be 32 ft or longer and 26 feet and shorter. Of course, in used ads by owners, you don't always know if the footage they quote is external o/a or internally. I feel like I should draw a line somewhere. I don't know however, what my overall max should be. We intend to travel 5 weeks or so annually in 1 week increments initially. I have seen some RV parks limit size to 30 foot, but being a newbie, am not sure if that is prevalent at many sites or is rare; is it o/a size or internal ? Is towing a 32 footer going to be dramatically different than towing a 28 footer ? I suspect the type of truck makes a difference also, but I think I have that covered.

I need the collective expertise of this forum to help me with some of these questions. I have already rcvd an education in RVing from the info on this forum and thankful to having found you folks. On this subject, any and all input into this would be appreciated.

Simple enough questions but all involve value judgments, so hard to answer.

28-30 feet is a common size, so not sure why you aren't seeing more. Maybe those owners are keeping their rigs longer? And size limits (if any) depend a lot on the region and the type of park you seek. The ones with smaller sites (and thus limits) tend to be older, or in more primitive surroundings (e.g. deep forests), or in rocky/hilly regions where carving out bigger sites is simply difficult. Length limits under 35 ft are not common in the Southeast, South or West, but somewhat more likley in the Northeast. Generally, though, I don't think limits under 30 ft are very common.  As to whether any stated size is LOA or interior or something else, it's anybody's guess. Campsite sizes tend to be based on some overall measurement at the site, i.e. a tape measured distance between two points. Maybe a tree at the back and the edge of the roadway. It may or may not have an allowance for parking the tow vehicle figured in. Frankly, it's a crap shoot and not something you can use for firm planning.

As for towing, a few feet makes no material difference. You might notice 32 ft vs 24 ft, but even that is seldom a big factor. Sometimes trailer (& truck) size becomes a factor on park access roads, but that is difficult to predict. Again, it it very specific to particular campgrounds and not a general factor.

I really think you ought to choose the size trailer that is comfortable for your living needs and accept that you will have to utilize parks where you fit. In most areas that won't be a problem. The exception would be if there is some park that is a "must" for you, e.g. all your friends go there or the fishing is great. In that case, I might limit my choice to what fits well there.

And just remember, if you get into a 5ver, there may be an issue with being able to tow it with a 3/4T truck.  It will depend on the Cargo Carrying Capacity of YOUR truck (not info from an advertisement)  and the amount of pin weight for a particular trailer.

^^ X2 ^^  The aux tank, and its' contents further reduce your payload. 

You should be fine with TT in your size range, but FW are likely completely out of the weight limits in the 30 ft range.

In your search, remember the CRITICAL factor is if you LOVE the Floor Plan!  All else is secondary.

A long TT should not be bad. However, a 30+ feet FW when you added an aux. tank will be too much for the truck.  Payload limitations.