Hi Wes M, once you are comfortable with domestic sales and handling customers I think it is worth going international.
As a UK seller I had a large amount of of old items sourced only from the UK which were in demand by collectors worldwide.
For me it was well worthwhile as much sold abroad and the items that did not were due to outbidding by UK buyers.
I only quote domestic rates on listings and ask non-UK bidders to ask for a quote before bidding, many don't but that is up to them.
Also I would only accept payment by PayPal and ship by air only, surface mail is a lot cheaper but the time scales for non-delivery are too long compared with eBay and PayPal dispute time scales so not worth it.
I also will not ship to Asia due to problems with China in particular (see references to BIN bandits over the last year or so).
You also need to ensure items are wrapped better for long hauls, customs were never a problem for items up to about £300 from the UK. Make sure buyers understand they are liable for any import duties payable on receipt by a short terms & conditions note on your listings.
Ensure you have the relevant custom stickers as applicable from the USA otherwise significant delays may occur in foreign customs (weeks to months) and with high value items add insurance.
Clear printed labels with address text copy-pasted from eBay invoices or PapPal notifications after ensuring they match, if in any doubt query with the buyer before dispatch.
Packing materials should include stout boxes and packing peanuts, the use of paper shreddings may be ok domestically but is very heavy when airmail prices may increment in 20g or ounce increments.
And most importantly get your postage rates worked out accurately as airmail is expensive because once quoted to a buyer you should never up it once they have won or paid for the item.
It is only hassle if you you do not pay attention to the details.